Most of the above are correct. Fims are really a paper ticket They are used for a number reasons: most common are when an e-ticket is showing used, a ticket cannot be involuntary rerouted, or another carrier refuses to accept a rebooked passenger with an award ticket (no value ). They are usually hand written by agents (NW is an exception - theirs are computer generated), and are usually 'good as gold' as far as the receiving carrier getting paid. In addition, they are usually not written exactly correct, and the receiving carrier frequently gets paid a full y fare. Carriers love to receive them and hate to give them.