There is no fee to cancel a UA ticket. The fee is to reissue the ticket — i.e., make it good for something else. Refundable tickets may have a fee for processing the refund, as well. But you can always call up and cancel for no fee.

The IRS considers the airfare tax on a non-refundable ticket to be non-refundable, even if you never use the ticket. PFCs are explicitly written into the law as being non-refundable on unused tickets. If you’re an American, feel free to take this issues up with your representatives in Congress.

As was originally stated, the TSA fees and various customs fees are all refundable, but I’ve yet to see any process put forth as to how to claim these refunds.