From ticket counters at major airports and from fuel pumps at the grassy strips favored by Sunday flyers, tax receipts are flowing once again into the Airport and Airway Trust Fund.

After more than two years of sometimes bitter debate in Congress and the aviation industry, the Federal Aviation Administration has a comprehensive development plan for airports and air traffic control -- and the means to fund it. Ticket and fuel taxes have been raised and are projected to finance $20 billion in capital and operating spending over the next five years.

The program is contained in the Airport and Airway Improvement Act of 1982, which Congress passed in August as part of the $100 billion tax package. It restored federal authority to make payments into the trust fund, which has received no deposits since 1980, when the legislation that created it expired.

"There's a sigh of relief from everybody that we now have a five-year bill," says one Department of Transportation official who follows aviation issues closely.

Many people in the aviation industry call the program far from ideal but backed it as better than no program at all. The most vocal criticism has come from the Aircraft Owners and Pilots Association, which represents operators of private plans. AOPA argues that the plan taxes members too heavily for things they don't use and has said it hopes to overturn it in future sessions of Congress.

The law, in effect since early September, imposed big increases in aviation taxes. Airline ticket taxes rose from 5 to 8 percent; tax on gasoline used by "general aviation," as private planes are known, rose from four to 12 cents per gallon; and the tax on general aviation jet fuel rose from zero to 14 cents per gallon. In addition, tax on air freight waybills rose from zero to 5 percent and a minor sales tax on tires and tubes remained the same.

The new rates are expected to raise about $2.4 billion in fiscal 1983 for the aviation trust fund. The fund, a sort of aviation counterpart to the older highway trust fund, was created in 1970 in response to the 1960s' rapid growth in air traffic and disbursed some $10 billion in the decade that followed. Taxes created for it were of the same rates as the new ones, with the exception of general aviation rates, which were lower.

In 1980, that law expired and taxes reverted to rates in force before 1970. Revenues now went not to the trust fund, but to other federal accounts. With nothing coming in to fund, Congress held spending from it to roughly the amount its balance was generating in interest. The industry, meanwhile, complained loudly that a huge surplus was building and should be tapped.

At present, there is about $4 billion in the fund, of which about half has been committed.

The new program calls for spending in four major areas: $4.8 billion for capital programs at airports; $6.3 billion for modernization of aging equipment in the air traffic control system; $1.2 billion for research and development; and $7.4 billion for the FAA's huge operating budget.

FAA officials are working to get final stamps of approval on $450 million in airport grants authorized for the plan's first year, fiscal 1982, before the year expires. Baltimore-Washington International is to collect $1.37 million to rehabilitate runway lights, rebuild taxiways and do other jobs, according to the FAA. Manassas Municipal Airport, a busy center for general aviation, will get $2.5 million for land acquisition and runway lights.

National and Dulles International Airport do not qualify for the program because both are owned and operated by the FAA.

Air traffic funds will go largely toward a mammoth modernization plan that FAA chief J. Lynn Helms unveiled earlier this year. It calls for replacement of computers, radar and communications equipment over the next 20 years and is being billed as one of the federal government's largest -- if not the largest -- nonmilitary procurements ever.

Many jobs now performed by humans would be given over to machines under the plan. Computers would devise flight paths that FAA planners say would reduce the need for the often circuitous and fuel-wasting routes planes now fly to stay apart from other traffic. Much of the new law's $1.2 billion for research and development would go to support this modernization.

The third major type of spending is for FAA operating costs. About 16,000 controllers now work at the more than 500 airport towers and traffic control centers across the country. Another 29,000 people are employed in other jobs such as traffic control support, flight standards, research and administration.

Congress passed no bill for two years in large part because of wrangles over "defederalization," a concept spearheaded by Sen. Howard Cannon (D-Nev.) to deny capital funds to big airports and require them raise their own money. The plan eventually died as the Reagan administration took office and disagreement continued as to who would pick up the difference and how.

The bill as passed preserved the previous law's basic structure for raising funds. But it vastly changed how they are divvied up. A much greater portion will now go to operating costs of the FAA -- the administration had supported this as an example of the user-fee concept in action -- and to air traffic control.

The White House's support for raising aviation taxes contrasted with its rejection of similar calls for higher gasoline taxes to finance work on the nation's highways. Many analysts feel the administration, while recognizing the need for more highway funds, felt that raising gas taxes would be too visible and unpopular. Raising aviation taxes, however, was politically less risky, in this view.

The Airport Operators Council International, which represents major U.S. airports, supported the plan as a compromise, out remains disappointed with what council spokeswoman Deborah Lunn calls its "overriding emphasis" on air traffic control. "Airports are not deliriously happy over it because the airport program itself is seen as a lower priority," she said.

Major airlines, represented by the Air Transport Association, also backed the plan, even though the major share of its funds will be raised by the ticket taxes their passengers pay. Airlines feel their long-term interests will be served by improving airports and the air traffic control system.

AOPA has emerged as the maverick among the associations, denouncing the plan in its magazine, AOPA Pilot, as "the worst single piece of legislation in the history of civil aviation." AOPA says its members do most of their flying in and out of small airports and under visual flight rules, which require pilots to stay clear of one another without the help of controllers. It is unfair to tax AOPA members heavily for a program that is going largely to pay for big airports and instrument flight, the association maintains. CAPTION: Picture, Ticket purchasers line up at the Baltimore - Washington International terminal, BWI will receive $1.37 million from airport trust funds for lighting, taxiway and other improvements.