If you're traveling by air this summer, flying by the seat of your pants may not be your best bet. According to a New York Times article, the number of fliers bumped due to overbooked flights is expected to peak for the decade this year. To avoid losing millions of dollars on empty seats, some air carriers use computer systems that factor in no-shows. Conflicts arise when too many passengers show up on popular routes and get bumped to the next flight, which can be a few hours or days later. Despite complaints, Thomas Trenga, vice president for revenue management at US Airways considers overbooking a necessary evil. Without overbooking, "we'd probably all go bankrupt," Trenga said. To make up for the added inconvenience, stranded passengers are given vouchers, which can vary from a small dollar amount to a round-trip ticket to anywhere an airline flies.--Jessica Chen