Expedia. On its app, the online travel agency Expedia offers Price Drop Protection on most flights. For a nonrefundable fee, the service will monitor the price of a flight booked through Expedia. If the price drops, the service will refund the difference.

Expedia offers a specific feature called Price Drop Protection™ that allows for a refund of the difference if the price of your flight drops on Expedia after you book. However, this is not a universal guarantee; it is a paid add-on or a benefit included only with "select" flight bookings. If you have this protection, Expedia automatically monitors your exact flight (same carrier, class, and route) daily until your departure. If a lower price is found, the difference is automatically credited to your original form of payment within 7 to 10 business days after you complete your trip. It is important to note that Expedia only matches its own prices—not those on other websites or "Member-only" rates. If you do not have Price Drop Protection, Expedia generally follows the airline's policy, which rarely includes refunds for price drops unless you have a flexible ticket that allows you to cancel and rebook without penalty.