Get ready to pay more when you fly.

The so-called Sept. 11 security fee that was intended to fund the Transportation Security Administration is about to increase. The TSA, however, says it won’t necessarily benefit from the extra revenue.

The fee hike could increase the cost of air travel by as little as 60 cents or as much as $22.40 or more, depending on the number of layovers and length of the stops.

TSA critics and the airlines are fuming about the hike.

"Why the increase?" wrote traveler Jon Berggren in a comment filed with the TSA. "When I go to the airport, I see two out of eight lanes open and 20 TSA agents walking around in circles and the line is out of the terminal. Where is all this money going?"

The increase, starting July 21, raises the security fee from $2.50 per leg with a $5 cap, to a flat fee of $5.60 per one-way trip with no cap. The cost of a round trip from Los Angeles to Orlando, Fla., with no layovers would increase from $5 in TSA fees to $11.20.

If the flight has long layovers, travelers will pay more.

Passengers will be charged a $5.60 fee for each leg of a trip if there is a layover longer than four hours, based on changes adopted by the TSA. In other words, a round trip from Los Angeles to Orlando, with stops of four hours or more in each direction, would incur fees of $5.60 for each leg, for a total of $22.40.

TSA officials say the agency is not getting a hike in revenue because Congress has directed the new fees to go to the U.S. Treasury to help reduce the government deficit. What’s more, Congress eliminated a separate security fee that generated $420 million a year for the TSA.

Airline officials say the fee hike is just another way the federal government is tapping an already highly taxed industry.

"Our government must stop using airlines and their passengers as its own personal ATM whenever it needs more money," said Vaughn Jennings, a spokesman for Airlines for America, a trade group for the nation’s carriers.