Why Does a One Way Ticket Cost More Than a Round Trip Ticket?

Airfare is notoriously difficult to predict, but some loosely defined "rules" have emerged that make it somewhat easier to make travel plans. One is that one-way airfare is almost always more expensive than a round-trip ticket. While this seems to defy conventional wisdom -- after all, you're getting two flights for less than the price of one -- airlines have relatively solid reasons for pricing flights this way.

Business travelers' airfare is typically round-trip and almost always purchased by a corporate travel department, which is generally more concerned with finding the most convenient flying times each way rather than the lowest cost. As long as there is a large market for non-discount round-trip airfare, airlines have little incentive to offer lower round-trip prices.

Airlines prefer that travelers fly round-trip simply because it is more convenient for their scheduling systems. Travelers who purchase one-way flights with the intention of purchasing another one-way ticket for the return journey make it difficult for airlines to make airplane staffing decisions and set flight schedules ahead of time.

It is common for passengers who need only a one-way ticket to take advantage of the lower round-trip fares, then simply discard the unused ticket portion. This is against airline ticketing rules, but it is almost never punished. When someone purchases a one-way ticket at a higher price than the cost of half of the same round-trip journey, the airline is able to adjust flight schedules without losing money -- whether the passenger decides to book a one-way return or not.

If you're not sure when you'll be returning, purchasing a one-way ticket seems logical. However, since the airline can't be sure you'll use them for the return trip, their one-way tickets are more expensive as a way to recoup the potential losses of you as a return passenger. You end up paying more for the convenience of deciding at your leisure exactly when you will return rather than making the decision at the time of booking.