The nation's airlines, with help from President Carter, are pushing a bill through Congress that would bring them more than $1 billion over the next five years.

The money would come from the 8 percent tax on airline tickets and the 5 percent tax on freight that are now used largely to build and improve airports.

Under a bill approved by the House Public Works Committee and now before the Ways and Means Committee, the airlines would be able to skim off a fourth of that money to buy new planes or refit or replace engines to meet federal anti-noise regulations.

The companies, the administration and supporters in Congress say the Airport and Aircraft Noise Reduction Act, which could give the industry at least $1.25 billion over the next five years, is the only solution.

But opponents see the idea as bad precedent, alternately calling it a "nightmare" and a "gimmick" that carries a "stink."

Questions and doubts have arisen in the Ways and Means Committee, largely because, in the words of Rep. Richard A. Gephardt (D-Mo.), "it is a bad precedent and bad tax policy that could establish a nightmare."

Industry and committee staff members were working yesterday to come up with an approach that might put the doubts to rest and still give the airlines the money they want. They reported little success.

The "nightmares" that Gephardt and others fear is that if the bill becomes law, it would open the door for other industries facing environmental requirements to obtain special revenue-raising favors.

The proposal is the brainchild of the Air Transport Association of America the airline companies' trade group, which says the industry can't fly anywhere - not to mention quietly - without it.

The commercial carriers' problem stems from the application of federal noise standards that first exempted existing planes and then were amended in 1976 to apply to all jet fleets - past, present, future - within eight years.

The Federal Aviation Administration says that about three-fourth of the U.S. carriers' 2,150 large jets do not meet the anti-noise standards.

The airlines say it will cost them $7.5 billion to replace noisy planes, replaced their noisy engines or remodel the engines to bring them into compliance.

So the problem for the financially beleaguered companies, most of which turn only a minimal profit even with the special investment tax credits they now enjoy, is the price of silence.

The device to which they have turned is outlined in the noise reduction act. They would use part of a tax assessed against passengers and freight to buy their quieter engines.

This year, that tax will raise about $1.7 billion.

That money goes into the Airport and Airway Trust Fund, administered by the government, to pay for some FAA operations, airport development and safety research.

But the fund takes in more money than it spends. It will have a surplus of about $2 billion at the end of fiscal 1978 this September. President Carter has proposed cutting the passenger tax to 6 percent and the freight tax to 3 percent because of that surplus.

The companies, however, have another thought. They are proposing that the 8 and 5 percent levies remain, but that they be allowed to take for their own use the amounts Carter proposed to cut.

It would work this way: the tax on a $100 ticket would remain $8. The industry would take $2 of that - each company holding the sum it collects - and other $6 would go to the trust fund.

While Treasury Department officials have given the plan only qualified support, the Department of Transportation would go even further.

The pendind bill would required each company to return unused money to the trust fund after it has quieted its engines. Transportation Secretary Brock Adams, in testimony this week, said the administration favors allowing each company to keep excess money after noise abatement is achieved.

Some other doubts about the bill stem from these points:

It would give the air industry alone the power to collect a tax to pay for equipment required to meet federal environmental standards - in this case, anti-noise regulations.

It would give private business, possibly for the first time, control over the expenditure of money it now collects as a tax on the federal government's behalf.

Doubts and questions notwithstanding, the airlines' financial dilemma over noise standards has whipped up some sympathetic reaction at Ways and Means.

Rep. Abner J. Mikva (D-Ill.), usually an opponent of any attempt to earmark tax money, said, "I don't know how else we're going to do it. Some companies oppose it. Some reformer oppose it. But how will we ever get the airlines to meet the standard - and it is good standard - without giving them some help?"

One answer was provided by Rep. Gene Snyder (Dy.), ranking Republican on the House Aviation SUbcommittee, who described the entire plan as "a wonderful gimmick."

"Why should we treat air carriers any differently from firms in other industries when it comes to the matter of meeting the costs of complying with federal environmental requirements?" he asked.