Too Sick to Fly: Which Illnesses Can Keep You From Travelling

Nicolle Harwood-Nash

By:  Nicolle Harwood-Nash

9 minutes read

Last Updated:  February 13, 2026

If you’re experiencing an illness, you’re likely not going to enjoy your flight, particularly long-haul flights. Apart from your enjoyment, flying when sick may also pose a risk to other passengers and may not conform to flight regulations in various parts of the world. If you’re flying with an illness, it’s an excellent idea to understand the regulations, as it might help you avoid unnecessary disruptions to your travel plans.

Here at AirAdvisor, we’re here to help you understand everything there is to know about flying when sick. In this article, we outline the illnesses you shouldn’t fly with, detail compensation eligibility for denied boarding because of an illness, and answer some frequently asked questions about flying while sick.

Can I Fly If I Am Sick?

Whether or not you can fly with an illness doesn’t have a ‘yes’ or ‘no’ answer. There are many factors that determine your travel eligibility. For example, if you have an extremely contagious sickness, you’re likely not allowed to board a flight. Some airlines, airports and countries also have their own policies regarding flying with an illness.

In most circumstances, even if you can board a flight while sick, you should consider the health and comfort of other passengers. Similar to going to work or school when sick, there’s a chance those around you may catch your illness.

What Are the Illnesses I Shouldn’t Fly With?

Here, you can find a list of some of the illnesses that may prevent you from flying:

• Infectious diseases
• Chronic obstructive pulmonary disease (COPD)
• Blood clots
• Recent stroke or heart attack
• Recent surgery
• Angina (chest pain at rest)
• Decompression sickness
• Intracranial pressure 
• Illnesses that require additional oxygen
• Shortness of breath at rest
• Untreated pneumothorax (perforated lung)
• Sickle cell disease

In general, flying poses unique challenges due to the changes in cabin pressure, reduced oxygen levels, and confinement in a small space. For many of the above medical conditions, these factors can exacerbate existing health issues, create new problems or infect other passengers.

Medical Flight - Your Only Alternative

If you can’t board a flight because of the severity or nature of your illness, a medical flight is usually your only alternative. Medical aircraft are equipped with machines and systems, allowing onboard health specialists to carefully monitor your condition. Specialised airlines usually offer medical flights, so if you’re flying with a standard commercial airline, you may have to book an alternative flight with a specific medical airline.

Another aspect to keep in mind is that, given the specialist nature of medical flights, the costs are usually substantially larger than flying with standard commercial airlines. Medical flights are primarily reserved for transporting patients between hospitals, responding to remote emergencies and transporting patients in critical condition. 

If your flight was delayed, canceled or overbooked within the last 3 years, you could be eligible for up to $650 (€600) in compensation.Check Your Flight

Can a Commercial Airline Deny Boarding If You Are Too Sick?

Yes, commercial airlines can deny boarding if you’re too sick, especially if the illness poses a risk to your health or safety, the safety of other passengers and crew members, or the overall operation of the flight. Airlines have the authority and responsibility to ensure the well-being of all passengers and the safe operation of their flights.

Here are some scenarios in which a commercial airline might deny boarding because of an illness:

• Contagious Illness: If you have a highly contagious illness, such as a severe cold, influenza, or a contagious viral infection, the airline might deny your boarding to prevent the spread of the illness to other passengers and crew members.
• Medical Unfitness: If your medical condition is severe enough to render you medically unfit to fly, the airline might deny boarding to ensure your safety during the flight.
• Risk of Complications: Some medical conditions can worsen during flight due to changes in cabin pressure, reduced oxygen levels, or other factors. Airlines might deny boarding to you if you’re at risk of complications during the flight.
• Medical Incapacitation: If you’re visibly ill or unable to take care of yourself, the airline might deny boarding due to concerns about your well-being during the flight.
• Disruptive Behaviour: In some cases, your illness might lead to disruptive behaviour that could interfere with the flight or the comfort of other passengers. Airlines have the authority to deny boarding to you if you pose a risk to the safety and comfort of the flight.

Do I Get  Compensation if I am Denied Boarding Due to Sickness?

Because airlines are obliged to prioritise the health and safety of passengers, you might not receive compensation for denied boarding due to sickness. Your compensation eligibility depends on several factors, though, including the specific airline’s policy, the circumstance of your denied boarding and the regulations of the country you’re travelling to and from.

Below you can review the standard regulations surrounding flying with an illness in the US, UK and EU:

US

The US has its own unique regulations for denied boarding because of sickness. If you have a transmittable illness and your presence aboard a flight poses a direct threat to passengers and aircrew, the airline typically compensates your flight by offering an alternative flight at a later date, usually up to 90 days after your initial denied boarding.

UK

In the UK, you’re typically not entitled to compensation if you were denied boarding because of your health. If you pose a threat to other passengers, such as through a contagious illness, you won’t receive any compensation.

EU

Similar to the UK, the EU offers no compensation when you’re denied boarding for reasons of health and safety. For example, if you’re denied boarding because of infectious respiratory issues, the airline likely doesn’t have to compensate you, as it’s their priority and duty to ensure the safety of passengers and crew. 

Flight delayed over 3 hours or canceled? See if AirAdvisor can get you compensation.Check Your Flight

Can I Fly if I Am Pregnant?

Yes, you can generally fly when you're pregnant, but there are some important considerations and precautions to keep in mind to ensure your safety and comfort during air travel. Each pregnancy is unique, so we advise you to consult your healthcare provider before making any travel plans, especially if you have any complications or specific health concerns.

Here are a few things to consider when flying while pregnant:

• Timing of Travel: Generally, flying is considered safer during the second trimester of pregnancy (weeks 14 to 27) when many common pregnancy discomforts have eased, and the risk of miscarriage is lower. However, travel during the first and third trimesters might also be possible with the approval of your healthcare provider.
• Health and Risk Factors: Your healthcare provider will consider your medical history, any pregnancy complications, and your overall health before giving you advice on whether flying is safe for you. Some conditions, such as preeclampsia or a history of preterm labour, might make air travel less advisable.
• Length of Flight: The length of the flight can impact your comfort and potential risks. Shorter flights might be more manageable than long-haul international flights. Prolonged periods of sitting can increase the risk of blood clots, which is a concern during pregnancy.
• Hydration and Nutrition: Stay hydrated throughout the flight by drinking plenty of water. Bring healthy snacks to maintain your energy levels and prevent low blood sugar.
• Comfort and Movement: Wear loose, comfortable clothing, and choose shoes that are easy to put on and take off. Consider wearing compression stockings to help improve circulation and reduce the risk of blood clots. Get up and walk around periodically to improve circulation, especially during longer flights.
• Safety Measures: Follow airline safety guidelines and buckle your seatbelt properly below your belly. Avoid using the overhead compartments for heavy bags and opt for bags that fit under the seat in front of you to give you more legroom.
• Radiation Exposure: While radiation exposure during commercial flights is considered minimal and safe, you might want to limit your exposure to cosmic radiation by minimising frequent long flights.

How Do I Get a Refund If I Am Too Sick to Fly?

If you’re too sick to fly, some airlines might offer refunds, alternative flight options or travel credit. This depends on the airline, though, as each airline typically has a unique policy in this regard. Low-budget airlines might be less likely to offer refunds compared to more established airlines.

If you’re denied boarding because you’re sick, there are several factors to consider to help secure airline compensation for being denied boarding due to illness:

• Contact the Airline: If you're too sick to travel and you know you won't be able to make your flight, contact the airline's customer service as soon as possible. Explain your situation and ask about their policies for obtaining a refund due to illness.
• Medical Documentation: Some airlines may require medical documentation, such as a note from your doctor, indicating that you're too sick to travel. Check with the airline about their specific requirements for medical documentation.
• Refundable vs. Non-Refundable Tickets: If you have a non-refundable ticket, getting a full refund can be more challenging. However, some airlines offer flexible policies in cases of illness. If you have a refundable ticket, you may have an easier time getting a refund, but still, check the airline's specific policies.
• Travel Insurance: If you purchased travel insurance, check your policy to see if it covers cancellations due to illness. Some comprehensive policies may provide coverage for documented illnesses that prevent you from flying.
• Timeframe: Act quickly. Most airlines have specific timeframes during which you can request a refund or make changes to your reservation. The closer you are to your travel date, the more challenging it may be to obtain a full refund.
• Online Booking: If you booked your flight through an online travel agency, check their specific policies and contact their customer service for assistance.
• Document Everything: Consider keeping records of all communication with the airline, including emails, phone calls, and any documentation provided by your doctor.

Find out if you are owed compensation for a disrupted flight.Check Your Flight

FAQs

Here you can find answers to some frequently asked questions about flying with an illness:

Can I fly if I’m sick?

As mentioned throughout the article, your eligibility to fly with an illness depends on the specific illness, the country’s regulations and the specific airline’s policies.

When am I too sick to fly?

In most situations, the airline may deem you’re too sick to fly when your illness poses a risk to your own health and safety, the health and safety of passengers and the general operation of the flight.

Author:

Nicolle Harwood-Nash

Job/Position: Writer & Content Creator

Nicolle is a copywriter and editor with over 15 years of international experience shaping content for industries including aviation, technology, finance, and healthcare. Skilled at both creative storytelling and precise editing, she brings adaptability and insight to every project she takes on.

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