New York ? Never mind the free lunch. Almost nothing is complimentary on airlines anymore, not even what many passengers consider a simple necessity: a single checked bag.

Under a plan announced Wednesday by American Airlines, passengers already forced to pay extra for amenities like earphones, meals and even snacks will have to pay $15 to check a basic piece of baggage.

Some other carriers are already charging for extra legroom in exit rows. What’s next?

“Pay toilets in the coach cabin maybe,” joked longtime airline consultant Mike Boyd.

But airline executives aren’t laughing, and other carriers refused to rule out similar fees to stow luggage in the cargo hold.

American Airlines’ plan is part of a larger effort by the industry to find new ways to improve revenue in the face of soaring fuel prices and a slumping economy. The airlines anticipated a multibillion-dollar loss this year, even before oil’s latest spike above $130 a barrel Wednesday.

Still, the latest effort could be a tough sell with passengers.

“It’s ridiculous,” said Louise Schum, a 23-year-old student from Steamboat, Colo. “Charging for luggage is the cutoff line.”

Fort Worth, Texas-based American announced the change at the same time it said it would slash capacity and retire at least 75 older, gas-guzzling planes. Gerard Arpey, chairman and chief executive of American parent AMR Corp., said the industry cannot withstand sky-high oil prices and must find ways to cover rising costs.

Travelers are likely to see other carriers follow suit, assuming the change becomes permanent.

“They’re always going to be looking for additional ways” to make money, said Ray Neidl, who monitors the airline industry for Calyon Securities. “Customers want low ticket prices, and they seem willing to pay for extra services.”