Q. I recently booked a $329 flight from Atlanta to Auckland, New Zealand, which was canceled only two days later. The tickets were on Air New Zealand but I purchased them via a third-party site. They emailed to say the fare was issued by mistake and was invalid. They did offer a refund, at least.

I've booked these types of mistake fares in the past and the airlines always honored them. Why didn't Air New Zealand honor this one?

A. The Department of Transportation has recently changed its approach to mistake fare, allowing airlines a little more wriggle room to cancel in the event of an error like this one. If you had gone on to purchase a non-refundable hotel in Auckland before being alerted that the tickets were invalid, the DOT does require the carrier to reimburse you for that along with any other non-refundable purchases you may have made as a result of your ticket.

Still, it's always a good idea to hold off on making additional hotel or tour arrangements until you're absolutely sure the airline plans to honor the ticket. If you haven't heard anything after 72-hours, you're probably in the clear.