Aviation lobbyists will be unusually unified today when they march to House and Senate Appropriations subcommittee hearings to complain about proposed cuts in the aviation trust fund.

The Federal Aviation Administration's trust fund is supported by taxes on airplane fuel and other items, with the 8 percent tax on airline passenger tickets the biggest revenue producer.

When the aviation lobby--everybody from the airlines' Air Transport Association to the Airport Operators Council International to the General Aviation Manufacturers Association--supported increasing the taxes, the understanding was that the money would be spent on airport reconstruction, navigational aids, improved computers for the air traffic control system and research and development.

When the trust fund taxes were modified and increased last year, so were authorizations to spend $783 million in fiscal 1984 on airports, $1.4 billion for facilities and equipment for the air traffic control system and $286 million for research and development.

Funds for the airport program--a favorite pork barrel on Capitol Hill--have since been increased to more than $900 million. But the other accounts aren't doing as well.

The Office of Management and Budget tried to cut funds for facilities and equipment to $800 million, but the FAA managed to make that figure $1 billion in the president's budget. The House Budget Committee agreed with that number, but the Senate Budget Committee cut it to $625 million.

The $286 million for research and development survived in the president's budget, but both budget committees reduced it to $134 million.

FAA experts say those cuts will slow the modernization of the air traffic system considerably, an assessment that worries aviation groups. * * *

SPEAKING OF COMMITMENTS . . . Arthur E. Teele Jr., chief of the Urban Mass Transportation Administration, irritated some of DOT's wheels when he appeared to recommend that the federal government provide no money for so-called "new starts" for rail transit systems in fiscal 1984. That happened the same day the OMB said that cost-effective new starts will be permitted (but not encouraged).

When Teele was asked at a House Appropriations subcommittee hearing about the administration's druthers, he said it would prefer to finance the backlog of rail modernization projects instead of new starts. But his prepared testimony said the same thing the OMB had said: cost-effective new starts will be considered. There was a bit of confusion and some angry politicians from Houston, Los Angeles and Atlanta, cities expecting money for new projects.

"Art got off the reservation," a senior DOT official said. Transportation Secretary Elizabeth Hanford Dole, accompanied by Teele, had met with presidential counselor Edwin Meese III and OMB Director David A. Stockman the day before to resolve a dispute between the DOT and the OMB.

According to an OMB official, Stockman had been "fighting a rearguard action" against funding new starts, despite an administration promise that some money from the gasoline tax increase could be spent on them.

Teele said yesterday that he had fought hard for new starts and that the administration's official position was reflected in his prepared testimony. "I would not say my testimony was a ringing endorsement of new starts," he said, "but I'm prepared to say we're working right now to determine the order and level of new starts that we'll be recommending to OMB and Congress before the markup is completed." * * *

THIS JUST IN . . . The Interstate Commerce Commission, remnants of which might one day become part of the DOT, put out a press release announcing that it supports and will actively participate in National Consumers Week, which is this week. The ICC invited consumers needing assistance with interstate moving companies, railroads, bus lines or trucking firms to contact one of its regional complaint centers. They are in Boston, Philadelphia, Atlanta, Chicago, Fort Worth and San Francisco.