Data from www.yapta.com show that booking air travel as early as possible makes an air traveler more likely to be eligible for a partial refund if the price for their ticket drops between when they purchased it and the date of their flight. The data show that someone booking airfare a month in advance of intended travel is more likely to get a refund of the difference if the price of his or her flight drops, than someone booking airfare only a week in advance. Someone booking airfare two months in advance is even more likely to get a refund of the difference if the price drops between the date of purchase and the intended date of travel. However, there was no indication that booking any further out than two months made someone even more likely to receive a refund after a price drop on his flight.
JetBlue and Alaska Airlines were discovered to be the two American-based carriers most likely to issue the difference to a traveler who purchased his ticket early, only to see the price drop. Airlines differed greatly in the average value of the travel credits refunded to passengers who book early, only to have the price of their flight drop. The values of the travel vouchers issued since April 2009 vary from under $100 for domestic flights with some airlines, to several hundred dollars for international flights with other airlines. To build brand loyalty among air travelers however, airlines will almost never issue a check for the difference on the spot. Instead, they will issue the difference in the form of a travel credit good for future travel on that airline. So really, an air traveler is still paying what he or she paid for their original ticket. And unless they fly relatively often, and demonstrate loyalty to the airline issuing the original ticket, the credit may go unused.