Citing its record fuel costs, Delta Air Lines plans to begin charging customers an extra $25 for checking a second bag.

The new charge, which takes effect May 1, follows moves by United Airlines and other carriers to add similar fees for transporting a second piece of luggage, which previously has been included in the price of the ticket.

"The change is due to rising fuel costs and ... the changing competitive environment we face today," Delta spokesman Kent Landers said Monday. "This is in line with general industry practices."

United and US Airways announced similar fees last month, to take effect in May. United, which is similar in size to Delta, estimated that its fee will generate about $100 million in cost savings per year, according to the Associated Press.

Chief Executive Officer Richard Anderson disclosed the new fee Friday, in a recorded weekly update to employees.

Landers declined to say how much money Delta expects to generate from the new fee. He said the fee will not apply to first-class or business-class customers or members of its frequent-flier program who log at least 25,000 qualifying miles of travel per year. Those travelers will still be able to check up to three bags without extra fees, said Landers.