Southwest's Rapid Rewards has 100% refundable tickets at points prices equivalent to the current non-refundable fare, provided that one of the 3 or so lowest nonrefundable fare classes is available. For domestic US travel this is hard to beat when you need to book a trip with a high probability of cancellation. If you cancel or even no-show, you get your points back and you can get the $5.60 security fee refunded too.

Avios bookings for US travel on AA or Alaska or US Airways are refundable in points if you cancel 24 hours or more before departure. You lose the security fee.

Southwest's senior fares (age 65, less than half off full fare) are fully refundable if you cancel at least 10 minutes before departure. Southwest's non-refundable fares are 100% reusable, for up to a year from original purchase date by the same passenger only, if you cancel at least 10 minutes before departure. If you don't have points yet, this is your best option to book a doubtful trip.