Why Do Planes Get Overbooked?

Overbooking is an airline's way of ensuring they have no empty seats at take off. It's exactly what it sounds like—an airline sells more tickets than they have seats on the plane. They do this to ensure a full plane when it comes to take-off. Empty seats are a financial drain on airlines.

What happens if a plane is overbooked?

But sometimes, passengers are bumped as a result of oversales practices. ... Before an airline forces a passenger to give up his/her seat due to overbooking, the airline must ask passengers on the flight if they are willing to give up their seat voluntarily in exchange for compensation.

How do airlines decide who gets bumped?

When there are more people with paid tickets than the aircraft can seat, bumping occurs. This process of freeing seats occurs in two ways. In the United States, the U.S. Department of Transportation requires airlines to seek out volunteers before requiring someone to give up a confirmed seat assignment.