Can an airline stop you from flying if you are sick?

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Yes, an airline can legally stop you from flying or remove you from a plane if you appear too sick to travel safely.

When Airlines Can Deny Boarding

Gate agents and cabin crew have broad legal discretion to refuse boarding or remove passengers under conditions such as:

  • Contagious or infectious diseases: Active symptoms of illnesses like influenza, COVID-19, chickenpox, or severe communicable sicknesses.
  • Active vomiting or bodily fluids: Passengers who are throwing up or cannot contain bodily fluids are often treated as a biohazard risk and removed before takeoff.
  • Inability to evacuate: Passengers too weak or impaired by illness or recent surgery to follow crew instructions or move during an emergency.
  • Deterioration in flight: Conditions that might worsen drastically due to cabin pressure changes (such as severe sinus infections, burst ear drums, deep respiratory distress, or late-stage pregnancy) or risks that could force an emergency medical diversion.

What You Need to Know

  • Medical Certificates: If you have a known contagious condition or a recent hospitalization, airlines like United Airlines may require a signed medical certificate from your doctor granting permission to fly.
  • Flight Changes and Fees: Policies vary by carrier if you choose to postpone a trip due to illness. While many airlines have dropped standard change fees for main cabin tickets, basic economy or international tickets may still incur penalties unless you have specific travel insurance or a medical waiver.

What illnesses can stop you from flying?

You should avoid air travel if you have an unstable, severe, or contagious medical condition that can worsen due to cabin pressure changes or put others at risk.

Respiratory Conditions

  • Collapsed lung (pneumothorax): Air trapped in the chest cavity expands at high altitudes and can worsen the condition.
  • Severe asthma or chronic obstructive pulmonary disease (COPD): Traveling is unsafe if you have trouble breathing at rest or low oxygen levels.

Cardiovascular Issues

  • Uncontrolled heart failure or unstable angina: Chest pain or severe breathlessness while resting means you should not fly.
  • Recent heart attack or stroke: You must wait until your condition is stable, often 1 to 4 weeks depending on medical clearance.

Infections and Blood Clots

  • Contagious infectious diseases: Illnesses like chickenpox, measles, active flu, tuberculosis, or COVID-19 require staying home to prevent spreading germs.
  • Deep vein thrombosis (DVT): Recent or active blood clots pose a high risk during long periods of sitting.

Surgeries and Other Risks

  • Recent major surgery: Procedures involving the chest, brain, eyes, or abdomen can be impacted by expanding gases in the cabin.
  • Unmanaged mental health: Severe psychiatric conditions that cause unpredictable behavior are unsafe for flight.
  • Late-stage pregnancy: Most airlines restrict travel past 36 weeks of pregnancy or for high-risk pregnancies.

You can learn more about general flight safety from the UK Civil Aviation Authority or review guidelines on Special Subjects in Merck Manuals.

What happens if you are sick and can't make your flight?

If you cannot fly due to illness, you must cancel your reservation before departure to request a fee waiver, travel credit, or refund, or you risk losing the ticket's value entirely as a no-show.

What Happens With the Airline

  • Denied Boarding: Gate agents or flight crews can stop you from boarding if you show signs of a contagious disease (like chicken pox, influenza, or COVID-19) or a severe medical condition unsuited for cabin pressure.
  • Change and Cancellation Fees: Many major airlines waive change fees or extend the value of non-refundable tickets into a future travel credit if you fall unexpectedly ill.
  • Documentation Required: Airlines generally require an official, dated letter or a completed medical declaration form from a licensed physician stating that you were medically unfit to fly on your departure dates.

What Happens With Insurance

  • Travel Insurance Claims: If you purchased a separate trip cancellation policy before falling ill, your medical documentation can be submitted to reimburse non-refundable prepaid costs like hotels, tours, and flights.
  • Credit Card Coverage: If you booked the fare using a premium credit card, check your card's built-in travel protection benefits, which often cover sudden medical emergencies.

Can an airline kick you off for being sick?

Yes, you can be denied boarding or removed from a plane if you are visibly sick.

Why Airlines Remove Sick Passengers

  • Flight safety: If your illness might cause a medical emergency or force the plane to land early (divert), the crew can stop you from flying.
  • Contagious risks: Showing signs of a severe or contagious illness (like persistent coughing, fever, or vomiting) threatens the health of other passengers and crew.
  • Emergency readiness: Crew members must ensure every passenger can take care of themselves or evacuate quickly during an emergency.

The Rules

Airlines write these rules into their official contracts of carriage. The flight captain has the final legal authority to decide if a passenger poses a health or safety risk. If the crew believes you are too sick to complete the trip safely, they can ask you to leave the cabin before takeoff.

What happens if you're sick before a flight?

If you get sick before a flight, you risk being denied boarding by the airline, worsening your symptoms from cabin pressure, or spreading illness to others.

Airline Policies and Denial of Boarding

  • Gate agents and crew: Staff have the right to deny boarding if you show clear signs of a contagious or severe illness (like persistent vomiting, high fever, or heavy coughing).
  • No-shows: Do not just skip the flight without telling the airline. Call before departure to avoid losing the value of your ticket entirely or being marked as a "no-show".
  • Medical waivers: Many airlines will waive change fees or extend ticket validity if you provide a doctor's note or medical certificate proving you were unfit to fly.

Health Risks of Flying Sick

  • Ear and sinus blockages: Cabin pressure changes during takeoff and landing can cause severe ear pain, ruptured eardrums, or blocked sinuses if you are congested.
  • Dehydration and fatigue: Recycled cabin air dries out your nasal passages and body, which can prolong your recovery time.
  • Contagious illness: Traveling with an active flu, COVID-19, or stomach virus puts other passengers and crew at risk.

What You Should Do

  • See a doctor: Get a dated medical certificate or a Fit-To-Fly statement immediately if you plan to request a refund or reschedule using medical provisions.
  • Contact your airline: Ask customer service about emergency rebooking or travel credit options.
  • Check insurance: Review your travel insurance policy if you purchased coverage; many plans cover trip cancellation due to sudden illness.

Ask Dr. Nandi: How to avoid getting sick on a plane, according to science

9 related questions found

What are some medical reasons to not fly?

While there is no single universal list, airlines and medical professionals advise against flying when a passenger has a medical condition that could be severely aggravated by lower cabin oxygen levels, changing barometric pressure, or prolonged immobility, or if the condition poses a safety risk to others.

The most common medical reasons to delay or avoid air travel include:

1. Cardiovascular and Blood Conditions

The minor drop in cabin oxygen pressure and the stress of travel can place dangerous strain on the heart.

  • Recent Heart Attack or Stroke: Most guidelines recommend avoiding flights for at least 7 to 14 days after an uncomplicated heart attack, and at least 2 weeks after a stroke.
  • Unstable Angina: Active, unpredictable chest pain means the heart muscle is not receiving enough blood flow, which can trigger a heart attack at high altitudes.
  • Severe or Decompensated Heart Failure: Individuals who experience breathlessness at rest or during minimal exertion are at high risk.
  • Uncontrolled Arrhythmias: Poorly managed irregular heartbeats can cause disabling symptoms mid-flight.
  • Severe Anemia: Severe cases (or sickle cell crises) leave the blood with a reduced capability to transport oxygen, exacerbating the effects of lower cabin pressure.

2. Respiratory and Lung Diseases

Airplane cabins are pressurized, but they still have less oxygen than at sea level.

  • Unresolved Pneumothorax (Collapsed Lung): This is a strict contraindication. Trapped air in the chest cavity expands as cabin pressure drops, which can cause life-threatening pressure on the lungs and heart.
  • Severe COPD or Asthma: Chronic conditions that cause severe shortness of breath at rest or require intensive oxygen management often require specialized medical clearance before flying.
  • Active Pneumonia: Fluid-filled lungs struggle to absorb oxygen, and the drop in cabin pressure can cause a passenger's oxygen levels to plummet to critical levels.

3. Recent Surgeries and Trapped Air

As an aircraft climbs, gas trapped inside the body expands by roughly 30%.

  • Abdominal or Thoracic Surgery: Trapped gas or air in the stomach, bowel, or chest can expand and tear healing internal sutures.
  • Recent Eye or Brain Surgery: Procedures involving the eyes (especially retinal detachment surgeries involving gas bubbles) or the skull can face dangerous pressure increases at altitude.
  • Recent Plaster Casts: Fresh casts (applied within 24 to 48 hours) can trap swelling extremities, restricting blood flow. Airlines often require a cast to be split before a flight.

4. Infectious and Communicable Diseases

To protect public health, airlines strictly reserve the right to refuse passengers with contagious illnesses.

  • Active Infections: Flying with highly contagious diseases like influenza, measles, chickenpox, or COVID-19 is prohibited until a doctor confirms you are no longer contagious and provides a "Fit to Fly" certificate.

5. Pregnancy and Infant Restrictions

  • Late-Term Pregnancy: Most airlines prohibit travel after the 36th week of a single pregnancy (or the 32nd week for multiple pregnancies like twins) to avoid the risk of preterm labor or delivery mid-flight.
  • Newborns: Infants less than 48 hours old are generally not allowed to fly, and many airlines require a medical clearance form for infants under 7 days old.

6. Other High-Risk Conditions

  • Deep Vein Thrombosis (DVT): A recent blood clot makes prolonged immobility in an airplane seat highly dangerous, as it increases the risk of the clot traveling to the lungs (pulmonary embolism).
  • Severe Ear and Sinus Infections: Severe blockages can prevent the ears from equalizing pressure during takeoff and landing, potentially leading to intense vertigo, severe pain, or a ruptured eardrum.
  • Unstable Mental Health: Acute psychiatric conditions or severe disorders that may cause agitation, confusion, or unpredictable behavior can threaten the safety of the patient and crew.
  • Uncontrolled Seizures: Poorly managed epilepsy can be triggered by flight stressors like sleep disruption, dehydration, and low oxygen.

Disclaimer: If you are experiencing symptoms or have an underlying medical condition, always consult your physician or specialist to obtain a formal clinical assessment before booking travel.

Why shouldn't you wear jeans on a plane?

You should avoid wearing tight jeans on a plane because they restrict blood circulation and worsen bloating caused by cabin pressure changes.

Health and Comfort Risks

  • Poor Circulation: Sitting for hours slows blood flow in your legs. Tight denim makes this worse and can raise the risk of deep vein thrombosis (DVT), a dangerous blood clot.
  • Cabin Bloat: Air pressure changes at high altitudes cause gas in your body to expand. A stiff, tight waistband digs into your stomach and causes pain.
  • Limited Movement: Cramped airplane seats leave no room to stretch. Stiff fabric rubs against your skin and restricts your muscles.

Practical Issues

  • Cramped Restrooms: Airplane bathrooms are very small. Stiff or tight pants make quick changes and bathroom visits difficult.
  • Security Delays: Metal buttons and thick zippers on jeans can trigger metal detectors or slow you down at security checkpoints.

Better Alternatives

  • Stretchy Pants: Choose soft joggers, leggings, or wide-leg palazzo trousers made with elastic or breathable fabric.
  • Soft Denim: If you must wear jeans, pick a loose-fitting style with 3% to 5% elastane or stretch fibers instead of stiff, heavy cotton.

Can I go on a flight if I have a cold?

Yes, you can fly with a mild cold, but cabin pressure changes can cause painful ear or sinus blockages.

When It Is Safe to Fly

  • Your symptoms are very mild, like a slight runny nose.
  • You do not have a fever.
  • You can breathe comfortably through your nose.

When You Should Not Fly

  • You have a fever or feel very sick.
  • You have severe ear pain, a sinus infection, or severe congestion.
  • You have trouble breathing or a deep cough.

Tips for Flying With a Cold

  • Take medicine: Use an oral or nasal decongestant 30 to 60 minutes before takeoff and before landing to help clear your sinuses.
  • Pop your ears: Chew gum, swallow often, or yawn during takeoff and landing to help equalize the pressure. You can also review advice from Johns Hopkins Medicine on relieving ear pain.
  • Stay hydrated: Drink plenty of water and avoid alcohol or caffeine.
  • Wear a mask: Protect other passengers by wearing a well-fitting mask during the flight.

Can an airline refuse to let you fly if you are sick?

Yes, an airline can legally refuse to let you fly if you are visibly sick or pose a health and safety risk to others.

Why Airlines Deny Boarding for Sickness

  • Contagious diseases: Staff can stop you from boarding if you show signs of an infectious illness like the flu, COVID-19, or chickenpox.
  • Visible symptoms: Active vomiting, persistent coughing, high fevers, or severe shortness of breath often trigger a refusal.
  • Medical unfitness: If a condition might worsen due to high-altitude cabin pressure—such as recent surgery, severe heart issues, or late-stage pregnancy—you may be barred.
  • Inability to care for yourself: If you cannot sit safely in a seat or require emergency medical help during the flight, the airline has the right to deny entry.

Passenger Rights and Rules

  • Contract of Carriage: Every airline includes a clause in its ticket agreement allowing them to refuse transport to sick passengers.
  • Medical Certificates: If you have a known contagious or serious condition, airlines may require a "fit to fly" note from your doctor.
  • Compensation: Airlines do not owe cash compensation if they deny you boarding for legitimate health and safety reasons.

For more advice on managing symptoms, you can read this guide on What to Do If You're Sick Before a Flight.

Can flying while sick make it worse?

Yes, flying while sick can make your symptoms worse due to cabin pressure changes, low humidity, and physical stress.

Why Flying Makes Illness Worse

  • Pressure changes: Altitude shifts during takeoff and landing change air pressure. If your ears or sinuses are blocked with mucus, your body cannot equalize the pressure. This can cause severe ear pain, sinus blocks, dizziness, or temporary hearing loss.
  • Dry air: Airplane cabins have very low humidity. This dries out your nasal passages and throat, which can worsen a cough or sore throat and slow down healing.
  • Dehydration: Low cabin humidity causes you to lose body fluids faster. If you have a fever or vomiting, flying increases your risk of dehydration.
  • Lower oxygen levels: Pressurized cabins have slightly less available oxygen. If you have chest congestion or shortness of breath, this drop can make it harder for your body to get enough oxygen.
  • Spreading germs: Travel fatigue weakens your immune system, and being in a crowded cabin increases the risk of passing your illness to others.

When You Should Avoid Flying

According to reporting from sources like The Washington Post and Healthline, you should consider delaying your trip if you have:

  • A fever
  • Shortness of breath or deep chest congestion
  • Severe ear or sinus pain
  • Contagious viruses like the flu, COVID-19, or a stomach bug

Users on Reddit generally agree that using oral decongestants, nasal sprays, and staying hydrated can help manage minor pressure discomfort if you must fly.