Airport Congestion Statistics: Understanding Passenger Impact in 2026
Some of the world's most important airports are simply full. London Heathrow operated 477,883 flights in 2025 against a legal limit of 480,000, and Amsterdam Schiphol finished the year just 448 flights short of the cap that applied from November. When demand presses against a fixed number of runway slots, the queue does not disappear. It moves onto the taxiway, into a holding pattern or into the security hall.
Why this matters: congestion is not the same as being busy. An airport with spare runway capacity can absorb a thunderstorm or a late wave of arrivals and recover within the hour, while an airport running at its limit all day passes every disruption down the line. This page treats congestion as a gap between capacity and demand: how many airports are formally slot-constrained, where Europe and the US hold flights because runways or controllers cannot cope, how long passengers queue on the ground, and whether new capacity will keep pace with forecast growth. For passenger rankings, see our busiest airports statistics.
Key Airport Congestion Statistics at a Glance
- 395 airports worldwide are subject to slot coordination in 2026, including 216 fully slot-coordinated (Level 3) airports.
Source: IATA, Airport Slots Fact Sheet, June 2026 - Around 43% of the world's passengers depart from a slot-coordinated airport.
Source: IATA, Airport Slots Fact Sheet, June 2026 - Heathrow regularly runs at around 99% of its declared capacity, according to IATA.
Source: IATA, Airport Slots Fact Sheet, June 2026 - Heathrow operated 477,883 air transport movements in 2025, 99.6% of its 480,000 annual cap.
Source: Heathrow Airport, full-year 2025 traffic release, 2026; Heathrow Airport Holdings annual report - Schiphol handled 477,552 flights in 2025; the Dutch Council of State annulled its 478,000-flight cap on 11 March 2026.
Source: Royal Schiphol Group, 2026; Raad van State, 2026 - Airport-related flow management delay averaged 0.68 minutes per flight in Europe in 2025, about 20,745 minutes a day.
Source: EUROCONTROL, Network Operations Report 2025, 2026 - Capacity and staffing limits caused 50.4% of airport flow management delay in Europe, more than weather (41.7%).
Source: EUROCONTROL, Network Operations Report 2025, 2026 (AirAdvisor calculation) - Chania in Crete recorded 8.30 minutes of airport ATFM delay per flight, the highest in Europe; Amsterdam logged the most minutes in total (579,738).
Source: EUROCONTROL, Network Operations Report 2025, 2026 - Newark averaged 13.01 minutes of air traffic system delay per arriving flight in 2025, 3.7 times the US average of 3.48.
Source: BTS, Airline On-Time Statistics and Delay Causes, 2025 (AirAdvisor calculation) - Only 49.2% of Newark arrivals were on time in May 2025, during a runway closure and air traffic control outages.
Source: BTS, Airline On-Time Statistics and Delay Causes, 2025 (AirAdvisor calculation; cancelled and diverted flights counted as not on time) - The FAA limits Newark to 72 scheduled operations an hour through 30 October 2027, down from a nominal target of 77.
Source: FAA, Federal Register notice, 23 June 2026 - Air traffic system delay at the FAA's Core 30 airports rose 31% in 2025, to 4.17 minutes per arriving flight.
Source: BTS, Airline On-Time Statistics and Delay Causes, 2024-2025 (AirAdvisor calculation) - 63% of passengers at eight UK airports queued 5 minutes or less at security in 2025; at Birmingham, 10% waited more than 20 minutes.
Source: Department for Transport, Air passenger experience of security screening: 2025, 2026 - 93% of US travellers surveyed perceived their TSA checkpoint wait as under 15 minutes.
Source: TSA, 2025 Passenger Experience Survey, 2025 - European airports will be unable to accommodate 1.1 million flights in 2050, 7% of demand, in EUROCONTROL's base scenario.
Source: EUROCONTROL, Aviation Long-Term Outlook 2024-2050, 2024 (F = forecast) - Airports handled a record 9.8 billion passengers in 2025; ACI's January forecast of 10.2 billion for 2026 predates a slowdown that held first-half 2026 growth to 0.6%.
Source: ACI World, Annual World Airport Traffic Report 2026, 23 September 2026; World Airport Traffic Forecasts 2025-2054, 2026 (F = forecast)
Congestion terms in plain English: Under the Worldwide Airport Slot Guidelines (WASG), published jointly by IATA, ACI and the Worldwide Airport Coordinators Group, a Level 2 airport is "schedules facilitated": demand is close to capacity, so airlines agree their timings with a facilitator. A Level 3 airport is fully slot coordinated: demand exceeds capacity, and no airline may land or take off without an allocated slot. ATFM delay (air traffic flow management) is the time an aircraft is held on the ground at its departure airport because its destination airport or the airspace along its route cannot accept more traffic. In the US, the equivalent congestion category in official delay data is NAS delay (National Aviation System), which covers heavy traffic volume, airport operations, air traffic control and non-extreme weather.
How Many Airports Are Slot-Coordinated?
An airport becomes slot coordinated when its runways, stands or terminals can no longer handle every flight airlines want to schedule. The decision rests with the national regulator, after a demand and capacity analysis. IATA's June 2026 fact sheet counts 395 airports under some form of coordination; seven years earlier, ACI counted 345.
Source: IATA, Airport Slots Fact Sheet, June 2026 (395 coordinated airports, 216 Level 3); ACI World Insights, The Importance of a Robust Slot Allocation Process (data as of June 2019, updated 30 September 2025). Level 2 in 2026 = 395 minus 216 (AirAdvisor calculation).
The fully constrained group has barely grown: 204 Level 3 airports in 2019 and 216 in 2026, a rise of 5.9%. The pressure shows one step down, where Level 2 airports rose from 141 to 179, up 27%, as more airports moved close to their limits. IATA's May 2025 fact sheet put the pace at an average of nine new airports declared Level 2 or Level 3 each year. Europe dominates the map: in ACI's 2019 count, 183 of the 345 coordinated airports were European. The US has far fewer. The FAA designates JFK as a Level 3 airport, treats LaGuardia as the equivalent of Level 3 and enforces slot rules at Washington National, while Newark, Chicago O'Hare, Los Angeles and San Francisco are Level 2.
Hubs Running at Their Limit: Heathrow, Schiphol, Frankfurt and New York
A handful of hubs show what "full" looks like in practice. Some have an annual cap set by planning law, others an hourly limit set by the air traffic authority. The table compares the limits that applied in 2025 and 2026 with each airport's latest traffic or punctuality figure.
| Airport | Capacity limit | Latest traffic or performance | Status (September 2026) |
|---|---|---|---|
| London Heathrow | 480,000 air transport movements a year (planning limit) | 477,883 movements in 2025 (99.6% of cap) | Draft Heathrow Expansion National Policy Statement published 18 June 2026; consultation closed 1 September 2026, with designation targeted by the end of 2026; third runway would add up to 276,000 flights a year |
| Amsterdam Schiphol | 478,000 flights a year from 1 November 2025, including 27,000 at night | 477,552 flights in 2025 | Annual cap annulled by the Council of State on 11 March 2026; 27,000 night-flight limit kept as an interim measure; the government plans a new decree keeping the 478,000 limit, expected from November 2026 |
| Frankfurt | Capacity value of 104 (plus 2) movements an hour at peak | 460,272 movements in 2025 (+4.4%) | DFS and Fraport will apply a refined operating concept once capacity reaches 110 movements an hour at the latest |
| London Gatwick | One main runway in routine use | 259,382 air transport movements in 2025 | Northern Runway consent order made 21 September 2025 and upheld by the High Court (23 June 2026) and the Court of Appeal (4 August 2026); up to 80 million passengers a year once in use |
| Newark Liberty | 72 scheduled operations an hour (36 arrivals, 36 departures) | 70.00% of arrivals on time in 2025 | FAA order extended to 30 October 2027 |
| New York JFK | 81 scheduled operations an hour, 6:00 to 22:59 | 75.43% of arrivals on time in 2025 | FAA order extended to 28 October 2028 |
| New York LaGuardia | 71 scheduled operations an hour, plus 3 unscheduled | 71.75% of arrivals on time in 2025 | FAA order extended to 28 October 2028 |
Source: Heathrow Airport, 12 January 2026, and Heathrow Airport Holdings annual report (480,000 limit); Royal Schiphol Group, 13 February 2026; Raad van State, 11 March 2026; Fraport, Traffic Figures 2025, 16 January 2026; DFS and Fraport, 4 June 2025; UK CAA, Annual airport data 2025 (Table 04a, movements excluding cancellations); The Gatwick Airport (Northern Runway Project) Development Consent Order 2025; FAA Federal Register notices of 23 June 2026; BTS on-time data, 2025 (AirAdvisor calculation). Utilisation = 2025 movements divided by cap.
Heathrow used 99.6% of its annual allowance, and Schiphol's 2025 total came within 448 flights of the 478,000 cap that took effect in November, which leaves almost no room to reschedule a cancelled flight on the same day. The New York airports show the American version of the same problem: JFK and LaGuardia operate under FAA slot orders first published in 2008 and 2006, and Newark joined them in practice in 2025. None of the relief is close. The UK government's target for a third Heathrow runway is 2035, and Schiphol's rules now depend on a new decision the Dutch cabinet has in preparation.
Why European Airports Hold Flights on the Ground
When an airport cannot accept every arrival, EUROCONTROL's Network Manager issues flow management regulations that keep inbound aircraft waiting at their departure gates. In 2025, airport-related ATFM delay averaged 0.68 minutes per flight across the network, against 1.67 minutes for en-route airspace delay. The split below shows why airports asked for those holds.
Source: EUROCONTROL, Network Operations Report 2025, Main report (edition 1.0, 4 May 2026), Figure 12. Values are average daily minutes of airport ATFM delay; "Other reasons" is derived as the 20,745-minute daily total minus the six labelled reasons (Figure 12 shows no labelled 2025 value for aerodrome events).
Weather was the largest single cause at 8,644 minutes a day, or 41.7%. But add aerodrome capacity (25.3%), airport air traffic control capacity (21.7%) and controller staffing (3.5%), and capacity-type limits account for 50.4% of airport delay. The trend is moving the wrong way for that half: EUROCONTROL reports that airport ATC capacity constraints rose 40.3% on 2024, mainly at Greek airports, while weather-related airport delay fell 11.4%. Airspace delays, strikes and knock-on disruption across the wider network are covered in our global flight disruption statistics.
Europe's Most Congested Airports by ATFM Delay
EUROCONTROL ranks airports across its network area, which includes Tel Aviv, by the flow management delay generated per flight. Two kinds of airport top the list: Mediterranean leisure airports that see huge summer peaks, and a few major hubs with no slack left in the schedule.
Source: EUROCONTROL, Network Operations Report 2025, Main report (4 May 2026), Figure 13, Top 20 airport reference locations. Network average airport ATFM delay: 0.68 minutes per flight.
Chania (8.30 minutes per flight), Athens (5.56) and Amsterdam Schiphol (4.90) head the table. Per-flight figures can make smaller airports look worse, and total minutes tell a different story: Schiphol was the most affected airport overall, with 579,738 minutes of delay, followed by Lisbon, Porto, Palma de Mallorca and Heathrow. Heraklion recorded the most delay attributed to aerodrome capacity, and Chania the most caused by ATC capacity. Heathrow (1.51 minutes) and Gatwick (1.34) both appear in the top 20, about twice the network average.
Arrived 3+ hours late?If your flight departed from the EU, or landed in the EU on an EU airline, and reached its destination 3+ hours late, you could be owed up to 600 EUR under EU261. Flights from the UK are covered by UK261, up to 520 GBP.Check Your Flight
Congestion at the Busiest US Airports
US airlines must assign every arrival delay of 15 minutes or more to a cause. NAS delay is the category that captures congestion: heavy traffic volume, airport operations, air traffic control and non-extreme weather. The chart measures it per arriving flight at the FAA's Core 30, the airports the agency uses to track system performance, which accounted for 4.78 million of the 7.74 million scheduled arrivals by reporting carriers in 2025.
Source: US Bureau of Transportation Statistics, Airline On-Time Statistics and Delay Causes (TranStats), January to December 2025, accessed 24 September 2026. NAS delay minutes divided by scheduled arrivals at each airport (AirAdvisor calculation). Orange bars = above the US average of 3.48 minutes for all airports. Core 30 list: FAA Aviation System Performance Metrics.
Newark stands apart at 13.01 minutes per arriving flight, 3.7 times the US average of 3.48. LaGuardia (7.31), Boston (6.83) and Washington National (6.20) follow, and JFK ties Denver at 5.91. Every New York airport is above average, which reflects the shared, crowded airspace they sit in. At the other end, Salt Lake City (1.24) and Honolulu (0.65) lost little time to the system. Across the Core 30, NAS delay rose from 3.18 to 4.17 minutes per flight between 2024 and 2025, an increase of 31%. For passenger and enplanement data by airport, see our US airports statistics.
Newark: What Happens When the FAA Caps an Airport
Newark's 2025 crisis stacked three problems at once. Runway 4L-22R closed daily from 15 April 2025 for rehabilitation, the Philadelphia facility that had taken over Newark's approach airspace in July 2024 was short of certified controllers, and telecommunications outages in late April and May disrupted radar and radio at that facility. The FAA responded with an order limiting Newark to 68 hourly operations from 10 June 2025 (56 during runway construction periods), then 72 from the winter 2025/2026 season, against a nominal target of 77 before the crisis.
Source: US Bureau of Transportation Statistics, Airline On-Time Statistics and Delay Causes (TranStats), January 2024 to July 2026, accessed 24 September 2026 (AirAdvisor calculation); FAA, Operating Limitations at Newark Liberty International Airport, Federal Register, 29 September 2025 and 23 June 2026; FAA, Statements on Newark Liberty International Airport, 2025. 2026 covers January to July only.
May 2025 was the low point: 49.2% of arrivals on time and 37.7 minutes of NAS delay per arriving flight. The cap cut capacity, and scheduled arrivals by reporting carriers fell 7.3% over the year, but it also restored predictability. In April and May 2026, 84.2% and 86.3% of arrivals landed on time, and January to July 2026 averaged 75.9% against 68.9% a year earlier. July 2026 (62.7%) shows the limits of the fix: summer thunderstorms still overwhelm a single-airspace system. The FAA's June 2026 extension says Newark's approach sector had 28 certified controllers against a target of 46 and does not expect the target to be met before the end of summer 2027, so the 36-arrival, 36-departure cap stays until 30 October 2027. JFK (81 scheduled operations an hour) and LaGuardia (71) remain under their long-standing slot orders until 28 October 2028.
Flying between the US and Europe?If your transatlantic flight departed from the EU or UK, or landed in the EU on an EU airline, and arrived 3+ hours late, you could be owed up to 600 EUR under EU261 or 520 GBP under UK261.Check Your Flight
Security Queues: How Long Passengers Wait on the Ground
Terminal congestion is measured far less systematically than runway congestion. The UK is an exception: the Department for Transport publishes official statistics from the Civil Aviation Authority's departing passenger survey, which asked more than 15,000 people at eight airports how long they queued for security in 2025. The figures are passenger perceptions, not timed measurements.
Source: Department for Transport, Air passenger experience of security screening: 2025 (Official Statistics, published 26 August 2026), Chart 2, based on the CAA Departing Passenger Survey. Figures are rounded and may not sum to 100%.
Across all eight airports, 63% of passengers queued 5 minutes or less and only 6% more than 15 minutes. Luton (80%), East Midlands (79%) and Gatwick (77%) had the highest share of short queues. Birmingham had the lowest (41%) and the longest tail, with 10% queuing over 20 minutes, though that was down from 16% in 2024. At the five airports surveyed every year, the share of passengers queuing 5 minutes or less rose from 52% in 2023 to 57% in 2024 and 64% in 2025, a period when UK airports completed their rollout of next-generation security scanners. Airports' own measures point the same way: Heathrow reported that over 97% of passengers waited under five minutes in December 2025, and Schiphol said 95% passed security within ten minutes on its busiest days of 2025. In the US, the TSA's May 2025 passenger survey (23,382 responses at 36 airports) found 93% perceived their wait as under 15 minutes. Daily checkpoint volumes are tracked in our TSA checkpoint travel numbers.
Can Airport Capacity Keep Up With Demand?
ACI World's latest long-term forecast, published in January 2026, expects 10.2 billion airport passengers in 2026 and growth of about 3% a year to 2054, when traffic would reach roughly 2.5 times its 2024 level. The near term has been weaker: ACI's 23 September 2026 traffic report confirmed a record 9.8 billion passengers in 2025 but growth of just 0.6% in the first half of 2026, with Middle East traffic down 21%. The regional split matters for congestion, because the fastest growth is not where most of today's constrained hubs are.
Source: ACI World, World Airport Traffic Forecasts 2025-2054, Executive Summary, January 2026. E = estimated (ACI preliminary 2025 regional totals from January 2026; ACI confirmed a 9.8 billion global total for 2025 on 23 September 2026). F = forecast. Growth rates are compound annual growth, 2024-2054.
Asia-Pacific is forecast to reach 10 billion passengers by 2054, and the Middle East is the fastest-growing region at 3.9% a year. Europe (2.4%) and North America (2.3%) grow most slowly, yet that growth lands on the airports already running closest to their limits. EUROCONTROL's long-term outlook quantifies the European gap: in the base scenario, 1.1 million flights, or 7% of demand, cannot be accommodated in 2050 because of airport movement limits, rising to 3 million (14%) in the high scenario. Airports in nine countries are expected to be capacity-limited, with the Netherlands facing a gap of 100,000 to 200,000 flights and continental Spain and Turkiye more than 200,000 each.
Outlook
The next two years will be decided more by rules and staffing than by concrete. Newark's cap runs until 30 October 2027 while the FAA trains controllers, Schiphol awaits a new airport traffic decree after its cap was struck down, and Heathrow's third runway is still at the national policy stage, with the policy statement due to be designated by the end of 2026 and a 2035 target for opening. In the meantime, the busiest hubs will keep running close to 100% of declared capacity, which means a single storm or equipment failure can cascade into hours of delay. Passengers can reduce their exposure by choosing early departures and longer connections at slot-constrained hubs; our peak travel season delay statistics show how much the time of day and month change the odds.
References and Sources
- IATA, Airport Slots Fact Sheet, June 2026
- IATA, Airport Slots Fact Sheet, May 2025 (archived copy)
- ACI World Insights, The Importance of a Robust Slot Allocation Process, 23 July 2019, updated 30 September 2025
- Heathrow Airport, Record year for Heathrow brings benefits to passengers and airlines, 12 January 2026
- Heathrow Airport Holdings Limited, Annual report and financial statements for the year ended 31 December 2018 (480,000 movement limit), 2019
- Royal Schiphol Group, Schiphol in 2025: quieter aircraft, more satisfied travellers and solid financial results, 13 February 2026
- Raad van State (Council of State), Afdeling bestuursrechtspraak vernietigt Luchthavenverkeerbesluit voor Schiphol, 11 March 2026
- NL Times, Government sticks to 478,000 Schiphol flight cap despite legal setback, 24 March 2026
- Fraport, Fraport Traffic Figures 2025: Broad Growth Across Airport Portfolio, 16 January 2026
- DFS Deutsche Flugsicherung, DFS and Fraport present refined operational concept for Frankfurt Airport, 4 June 2025
- UK Civil Aviation Authority, Annual airport data 2025 (Tables 04a and 06), 2026
- UK Government, The Gatwick Airport (Northern Runway Project) Development Consent Order 2025, made 21 September 2025
- London Gatwick, Northern Runway Plans, accessed 24 September 2026
- UK Department for Transport, Heathrow Airport Limited's third runway proposal will be basis for expansion, 25 November 2025
- UK Department for Transport, Draft Heathrow Expansion National Policy Statement, 18 June 2026
- Heathrow Airport, Our third runway expansion proposal, accessed 24 September 2026
- EUROCONTROL, Network Operations Report 2025, Main report, edition 1.0, 4 May 2026
- EUROCONTROL, Aviation Long-Term Outlook: Flights and CO2 emissions forecast 2024-2050, December 2024
- US Bureau of Transportation Statistics, Airline On-Time Statistics and Delay Causes, data through July 2026, accessed 24 September 2026
- Federal Aviation Administration, ASPM: Core 30 airports, accessed 24 September 2026
- Federal Aviation Administration, Operating Limitations at Newark Liberty International Airport (extension of order), Federal Register, 23 June 2026
- Federal Aviation Administration, Operating Limitations at Newark Liberty International Airport, Federal Register, 29 September 2025
- Federal Aviation Administration, FAA Statements on Newark Liberty International Airport, April to June 2025
- Federal Aviation Administration, Operating Limitations at John F. Kennedy International Airport, Federal Register, 23 June 2026
- Federal Aviation Administration, Operating Limitations at New York LaGuardia Airport, Federal Register, 23 June 2026
- Federal Aviation Administration, Notice of Submission Deadline for Schedule Information, Winter 2026/2027, Federal Register, 23 June 2026
- UK Department for Transport, Air passenger experience of security screening: 2025, 26 August 2026
- Transportation Security Administration, TSA 2025 Passenger Experience Survey, 2025
- ACI World, World Airport Traffic Forecasts 2025-2054, Executive Summary, January 2026
- ACI World, ACI World releases global airport traffic forecasts as long-term demand growth continues to reshape aviation, 28 January 2026
- ACI World, Global airport passenger traffic reaches record 9.8 billion in 2025, 23 September 2026
Methodology Note
Coordinated airport counts come from IATA's June 2026 fact sheet (395 coordinated, 216 Level 3); the 2026 Level 2 figure (179) is derived by subtraction, and the 2019 comparison uses ACI's count as of June 2019 (204 Level 3, 141 Level 2), so the two years come from different publishers applying the same WASG definitions. Heathrow and Schiphol utilisation divides each airport's reported 2025 movements by its cap; Schiphol's 478,000 cap applied only from 1 November 2025 and was annulled in March 2026. Gatwick movements are UK CAA air transport movements excluding cancellations. European delay figures are EUROCONTROL airport ATFM delay (arrival regulations at the reference airport); the "Other reasons" slice (322 minutes a day) is the stated daily total of 20,745 minutes minus the six reasons EUROCONTROL labels, and capacity-type causes combine aerodrome capacity, airport ATC capacity and ATC staffing. US figures are AirAdvisor calculations from the BTS delay-cause file for carriers that report to the Department of Transportation: on-time rate = scheduled arrivals minus arrivals delayed 15 minutes or more, cancelled or diverted, divided by scheduled arrivals; NAS delay per flight = NAS delay minutes divided by scheduled arrivals at that airport, which assigns delay to the arrival airport even when the constraint was elsewhere in the system. UK queue times are passenger-reported survey results, not timed measurements. ACI's 2025 regional totals are the preliminary figures from its January 2026 forecast (marked E); ACI's 23 September 2026 traffic report has since confirmed a global total of 9.8 billion, so regional values may differ slightly, and 2054 values are forecasts (F) made before the 2026 Middle East airspace disruption; EUROCONTROL's 2050 capacity gap is a forecast. Percentages were computed from unrounded source data where available, so they may differ slightly from calculations on the rounded figures shown.
Author:
Amy LancelotteJob/Position: Senior Writer & Content Strategist
Amy Lancelotte is a Senior Content Writer and editorial contributor at AirAdvisor with over seven years of experience producing research-based articles for international audiences. Her work focuses on travel, aviation, and air passenger rights, with an emphasis on factual accuracy, verified data, and clear, reader-first explanations.
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