Purchasing airline tickets can be frustrating as the cost is often a moving target. The U.S. Department of Transportation now mandates that US airline carriers allow consumers to put a flight “on hold” without fear of a price increase for up to 24 hours OR cancel within 24 hours for a full refund. The purchase has to be at least seven days prior to departure and must be made directly with the airline. Currently, American Airlines is the only US airline that allows you to hold a flight for 24 hours without cost; others have opted for a free 24-hour cancellation period.