After a video of a passenger being dragged off a plane went viral in 2017, many frequent flyers are wondering what their rights are when it comes to an overbooked flight. While it helps to motivate passengers to volunteer (many times in the form of a voucher), it turns out that in many cases, airlines are required to compensate a passenger when they overbook a flight. Here are your traveler rights for flight compensation when dealing with an overbooked flight, canceled flight, or delayed flight.

Overbooked flights: Involuntary bumping

Delay of one to two hours

For involuntary bumping, The Department of Transportation’s regulations say that “if the airline arranges substitute transportation that is scheduled to arrive at your destination between one and two hours after your original arrival time (between one and four hours on international flights), the airline must pay you an amount equal to 200 percent of your one-way fare to your final destination that day, with a $675 maximum.”

That payment is to be in the form of cash or check.

Delay of more than two hours

If an overbooked flight delays you more than two hours (or more than four hours on international flights), you must receive 400 percent of the one-way fare, up to $1,350.

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However, if you arrive within one hour of your original arrival time, the airline does not have to compensate you at all.

And for volunteers, the rules are completely different. Involuntary bumping is only if they have asked for volunteers and no one volunteers — and so they force you to take another flight.

Overbooked flights: Voluntary bumping

Voluntary bumping is completely different, but a much more common occurrence because some travelers like to receive the voucher for future travel.

“DOT has not mandated the form or amount of compensation that airlines offer to volunteers,” the department said. “DOT does, however, require airlines to advise any volunteer whether he or she might be involuntarily bumped and, if that were to occur, the amount of compensation that would be due.”

According to DOT, if the airline offers you a free ticket or voucher in a certain dollar amount, you should ask them about any restrictions, like an expiration date or any date or destination blackouts.

Delayed or canceled flights

Contrary to popular belief, airlines are not required by federal law to offer any form of compensation for canceled or delayed flights.

“If you are delayed, ask the airline staff if it will pay for meals or a phone call,” DOT said. “Some airlines, often those charging very low fares, do not provide any amenities to stranded passengers. Others may not offer amenities if the delay is caused by bad weather or something else beyond the airline’s control.”

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Many airlines will do what they can to put you on their next flight, but many of them will not give you compensation unless the cause is mechanical. That being said, I have been delayed based on weather, and have learned you can usually talk the Customer Service desk to provide some sort of meal coupon, even though they are not required to offer you anything.

Every airline is different

Airlines will choose which passengers to bump in different ways. For instance, American Airlines says who they choose is at the discretion of American Airlines employees, but they consider factors like hardships, fare paid, and status within their loyalty program. Their official rules say that they will not deny boarding to anyone until they first ask for volunteers, in exchange for compensation “of the airline’s choosing.”

Each airline is different, but most do have rules listed on their website — so it may be worth knowing the airline’s rules and regulations before even arriving at the airport.