Presently, full meals start on American flights of two hours.
The changes are meant to align practices at American and US Airways, which in April cut its minimum flight time for a first-class meal to two hours and 45 minutes from 3½ hours.
The rules will apply to travel in the United States, Canada, Mexico, and the Caribbean, as outlined on American's website at aa.com/arriving.
Passengers on 17 popular routes for business travelers that are less than two hours and 45 minutes, such as Philadelphia-Minneapolis, Dallas-Chicago, New York-Chicago, and Miami-Houston, will continue to get full meal service in first class, American said.
On flights of less than 60 minutes, first-class passengers will get a "packaged snack," while on flights of one to two hours, they will get a snack basket with "a variety of sweet and savory snack options," according to an e-mail to members of American's AAdvantage frequent flier program.
Flights between two hours and two hours and 45 minutes will receive a "Lite Bites" snack basket with fresh fruit, breakfast breads or sandwiches, and packaged snacks.
First- and business-class fliers airborne between two hours and 45 minutes and 3½ hours will get warmed mixed nuts, a three-course meal, and a warm cookie.
"Airlines are making money - millions of dollars now - and they are still cutting costs," said George Hobica, founder of Airfarewatchdog.com. "It seems bizarre to me that they are diddling with their first-class customers. Is nothing sacred?"
"What will they do next - take off the sprig of parsley from the salad? Substitute paper napkins for cloth?"
Hobica recalled that in 1987, Robert Crandall, then head of American Airlines, came up with the idea of removing one olive from every salad served in first class. The passengers would not notice, and the airline could save $40,000 a year.
"They are still going to have meals on the most popular flights that affect the most people," Hobica said. "It just seems like unnecessary cost-cutting to me."
American spokesman Casey Norton said: "It's all about delivering a consistent product all across the system, no matter which carrier you fly."
"What we expanded on US Airways, now we are meeting with an American product, too. We have to have everything aligned when we are finally one carrier."
Economy travelers in the back of the plane have long paid for food and alcohol on domestic flights.
International travelers in coach and first and business classes will still get complimentary meals on flights longer than 31/2 hours.
Delta offers a complimentary cookie, pretzel, or peanuts in first class on domestic flights up to 250 miles, and "heartier" snacks for trips of 251 to 899 miles, according to its website.
A full meal is provided on flights of 900 to 1,499 miles, and a meal and snacks on flights of more than 1,500 miles.
For first-class passengers, United offers cookies or pretzels and a beverage of choice on domestic routes of one hour or less; breakfast scones or snacks and fresh fruit on trips of one hour to 21/2 hours; and a meal during "meal times" after 21/2 hours. On flights longer than five hours, first-class passengers get a meal with snacks, United said on its website.