The Wall Street Journal reported that airlines are considering charging fees for higher-end food and even champagne brunches.
Delta is set to offer seats that recline farther than normal seats with extra legroom for more money.
Already, many airlines are offering customers the opportunity to board ahead of other passengers, but that comes with an added fee, too.
Also, airlines are boosting their ticket prices, with Southwest Airlines recently joining a sweeping increase of $10 in the price of many domestic round-trip airfares.
This is the sixth time airlines have raised fares in 2011. The airlines are citing the need to offset high fuel prices as a reason for the higher ticket costs.
Jet fuel prices have risen more than 50 percent in the past year to more than $3 a gallon, although most airlines have offset some of the increase through hedging - in effect, paying extra to lock in the top price they'll pay for some of their fuel.
The latest round of price hikes started early last week when Delta Air Lines Co. tried to raise many fares by up to $20 per round trip. Other big airlines sided with a $10 increase started by American Airlines.
Three days later, Southwest matched American's move. Other airlines had rolled back fare hikes on routes where they compete with Southwest and other discount carriers, but they revived the full increase once Southwest raised prices too, said FareCompare.com CEO Rick Seaney.
Low-cost airlines JetBlue, AirTran and Virgin America also raised prices, virtually assuring that the increase will become permanent, Seaney said.
There were only four broad price increases in all of 2010, and two of those occurred in December.
The Associated Press contributed to this report.
