Beware of hidden fees when you fly.(air travel cost management)

For the past decade, competition from low-cost carriers and Web sites that offer cheap seats have combined to keep a lid on airline-ticket prices, but that may be changing. Leisure fares spiked 15 percent this year, thanks in large part to rising fuel costs, says Bob Harrell, president of Harrell Associates, an airline-consulting company.

And that's not all. Like hotels and financial-services companies, airlines are padding basic fares with pricey "gotchas." In the first half of 2005, the nine largest U.S. airlines charged nearly a half-billion dollars in excess baggage and reservation-cancellation fees--a 250 percent increase over the same period in 1995 and far greater than the 9 percent jump in the number of passengers on those carriers. And those numbers don't include new fees created in recent years. The table at right shows how quickly the dollars can add up.

WHAT THE FEES ARE FOR

Many of the newest fees are for former freebies, such as food (US Airways and United, for example, charge $5 for a snack box) and booking a ticket on the phone with an airline reservations clerk ($8 to $10 for some carriers). Most airlines are also enforcing long-standing excess-baggage fees that many check-in agents used to overlook. For international flights on Northwest, for example, a $25 excess-weight fee kicks in at 51 pounds, not the old 71. At Continental, a checked stroller and child safety seat will use up your allotment of two bags per ticketed passenger, and each extra bag will cost from $80 (for a third bag) to $180 (for a seventh or more).

Fees get you coming and going: Delta adds 10 percent to the price of Mom's international ticket for an infant who sits on her lap, while US Airways has raised its price to $80 for the air tray required for a casket. Last year Delta raised the fee for a minor traveling on nonstop flights without an adult to $50 each way.

Critics maintain that many fees are for services that cost the airline virtually nothing. "It doesn't cost the airline $100 to change your reservation," says Michael Boyd, president of the Boyd Group, an airline-consulting firm. "They're being opportunistic."

Most likely to charge extra fees are older airlines trying to fend off competition from newer, lower-cost carriers that don't offer the service or can deliver it without charging extra. That puts the older ...