The Air Transport Association, which represents most major U.S. airlines, said yesterday that a federal corporation "offers considerable promise" as an alternative to the air traffic control system operated by the Federal Aviation Administration.

The conclusion comes in a carefully worded report that reflects airline irritation about the constraints the air traffic control system puts on growth. The airlines collect an 8 percent federal ticket tax for the aviation trust fund, which is supposed to be earmarked for air traffic operations and equipment, but $3 billion of the fund has not been obligated.

The report says that the "FAA's budget, including the trust fund portion, is subject to the complexities of Congress' annual budget resolution and appropriations struggle, involving more trade-offs, compromises and further blending."

FAA Administrator Donald D. Engen declined to comment but said he would "be interested in looking" at the report.

The ATA's proposal for a federal corporation is a somewhat different answer from that offered by the conservative Heritage Foundation, which has suggested in its "Mandate for Leadership" books that the air traffic system be operated by private industry.

The standard governmental response is that private employes can strike while government employes cannot and that the air traffic system has considerable national defense responsibilities, which can only be guaranteed by a government agency.

The airlines supported President Reagan's firing of 11,400 FAA air traffic controllers who struck in August 1981 but have been concerned that the FAA is not rebuilding the system quickly enough.

"The ability of the system to respond in a businesslike way to market demands for air traffic control service must be unfettered," the report said. "In the case of the airlines, the need to deploy assets as productively as possible, as called for by airline deregulation, requires a corresponding response in the provision of . . . services."

The current system, the ATA said, "does not permit effective, businesslike decision making and innovative planning of the kind required to operate an air traffic control system established for the predominant purpose of meeting public demand, and being paid for predominantly by the using public."

The ATA outlined an independent corporation whose personnel would be U.S. employes, outside of civil service. The corporation would be self-sustaining from user fees. The airlines have long felt that they are subsidizing military and general aviation users of air traffic services.