Major carriers keep finding ways to nickel and dime fliers.

By Donna Rosato Money magazine staff writer
April 30 2007: 3:41 PM EDT

NEW YORK (Money) — Travel alert: You’ll be paying more to fly this summer on planes that are more crowded than ever - even after you’ve bought your ticket.

Airlines are set to fly with record full flights this summer, with air fares at their highest level since 2000. Major carriers like Delta, which emerged from bankruptcy protection Monday, are operating leaner operations, making it harder for fliers to find alternatives when there are delays and cancellations.

On top of all that, both legacy and low-cost carriers are instituting a host of fees for travelers.

A recent report by the Department of Transportation found that the average domestic air fare was $378 roundtrip, the highest level since 2000. And for airlines to survive, they may have to do even more to raise revenue.

“Airlines are constantly in search of new revenue sources,” said Chris McGinnis, editor of The Ticket travel newsletter.

Travelers have gotten used to paying for food on board. But it’s going to be harder to adjust to fees for services that used to be free, said McGinnis.

Here are some new or higher fees fliers are likely to encounter:

Seat assignments
Checking bags
Fuel surcharges
Flying standby