What you're owed when an airline cancels a mistake fare

Under the DOT's 2015 mistaken-fare policy, an airline may cancel a ticket sold at an erroneous fare if it can show the error, refunds the ticket and reimburses reasonable, verifiable expenses you incurred relying on the booking. American's own conditions of carriage add a promise to notify passengers within 72 hours of discovering the mistake. If you book a likely mistake fare, hold off on nonrefundable hotels and visas until the ticket has survived a few days, and keep receipts for anything you do spend.