Did you know that all airlines overbook flights by at least 10%?
Yes, this is true. This happens because airlines want to protect themselves in the case of cancellations and no-shows. There will always be people not showing up for their flights or those who need to cancel a trip at the last minute. If airlines do nothing, there will be many empty seats on planes and airlines might not be able to fill those up the last minute. Therefore, airlines sell more tickets than there are seats on the plane.