The fee changes, which went in effect April 2, come as Delta and its competitors try to boost revenue to offset record fuel prices. Delta did not say how much revenue it expected from the fee changes, but the parent company of United Airlines said new luggage fees would generate more than $100 million annually. The industry has had mixed success with fare increases.

“Desperate people do desperate things,” said Minneapolis airline expert Terry Trippler.

Betsy Talton, a spokeswoman for Delta Air Lines Inc., the country’s third-largest carrier, said Delta’s additional fees are largely in response to fuel prices and said that the most recent attempts by Delta to raise fares “have not been successful because there’s also a need for Delta to be competitive.”

Talton said Delta continuously reviews all aspects of its business “to make sure our business model is aligned with current costs.”

She said she did not know how much extra revenue the airline expected to generate annually from the fee changes.

One of the changes most likely to rankle frequent fliers is a new $25 “handling charge” for any Delta award ticket booked through a Delta representative that includes a segment on another airline. In the past, people who redeemed their Delta SkyMiles for free tickets on partner carriers like Northwest and Continental did not pay a “handling charge” whether they booked it on the phone or online.

The fee for booking an award ticket on another airline through a Delta representative helps Delta recoup charges from the other airline, Talton said. Booking Delta award travel on another airline will not carry the new $25 fee if done online, Talton said.

The “handling charge” would be on top of the fee Delta charges for booking travel over the telephone, which is increasing April 2 to $25 from $20.