You Can Almost Always Cancel Your Flight FOR FREE Within 24 Hours... After They Get Cheaper

Everyone knows you can cancel your flight within 24 hours of booking... right?

Wrong. We didn't really realize this was possible until recently, when we learned it's a federal rule for airlines to give passengers a full refund if they choose to cancel their flights within 24 hours of booking, provided they book more than seven days before their trip.*

And 68 percent of the time, ticket prices do drop within that 24-hour window, according to a recent study from Hopper. So all those times you booked your flight, then saw a better deal just hours later? Yup, you could've cancelled and re-booked them for a lower price. On average, this price is 14 percent lower than the original.

As Hopper notes, eight major U.S. airlines offer free cancellation for tickets purchased at least seven days in advance: Delta, United, US Airways, JetBlue, Southwest, Spirit, Frontier and American (in American's case, you'll "hold" your ticket instead of purchasing it). And most of these let you cancel your ticket for free EVEN IF you booked within seven days of departure (exceptions include JetBlue, US Airways and Spirit).

Of course, you've gotta look out for the tiny loopholes -- the 24-hour rule may not apply to things like rewards travel or trips booked through third party websites. Expedia, for example, states that passengers "may have the option to cancel" for a refund but doesn't guarantee it.

But if you're booking flights at the recommended 54 days before your trip, you're most likely in luck. The first flights you book don't have to be the ones you take.

...just take a price break instead.

CORRECTION: A previous version of this post stated that airlines must either hold your flight for 24 hours after booking OR allow you to cancel for a full refund. In fact, they must do both.