The Marines are in a new kind of fight, this one with Defense Secretary Harold Brown over their right to a modern air force.

Marine leaders contend that their air force is the extra punch they need to combat heavier but slower enemy forces, with the Warsaw Pact the threat now being cited.

Brown and his deputies counter that the corps, which through the years has prided itself on going lean, can go leaner and cheaper when it comes to planes.

The outcome of this battle will shape the future of the Marine Corps, with critics contending that its air wings are already taking too much money away from the ground forces, which should get top priority.

This new battle, being fought with budget analyses and counteranalyses written in the old Marine Corps headquarters alongside Arlington Cemetery and in Pentagon offices, will be joined in a formal way next week.

Marine Corps Commandant Louis H. Wilson, Navy Secretary W. Graham Claytor Jr. and Adm. James L. Holloway, chief of naval operations, are scheduled to meet with Brown Wednesday to appeal budget cuts he has tentatively decided to make in their separate air forces.

For both, Marine and Navy leaders, Brown's most worrisome actions were those taken against the new generation of plane called VSTOL for vertical and short take-off and landing.

Marine leaders concede that they probably will not be jumping off landing barges to secure a beachhead in this age of "smart" weapons. So they instead envision flying troops over the beach by helicopter and supporting them with flying artillery - planes armed with bombs, rockets and guns.

The plane Marine leaders have been counting on most to give them that extra punch from the air in the future is a new model of the V/STOL Harrier designated as the AV-8B.

But Brown, in drafting what is called a presidential decision memorandum, decided the Marines could get along with the A-4 Skyhawk attack plane for supporting infantry rather than buy the new Harrier any time soon.

This would save money in the defense budget, which, despite such cuts, will keep going up in the future.

In another action which upset the Marine leadership, Brown recommended in his presidential decision memorandum drafted for President Carter that the Marines reduce their F-4 phantom squadrons from 12 to nine.

If this reduction is imposed, Marine leaders contend that the nation's current shortage of planes for air defense will become even more severe. The Marine F-4s are used primarily for escorting bomb-laden attack planes to their targets. Each Marine squadron consists of 12 F-4s.

The combination of being forced to rely on the A-4s instead of the advanced Harrier and making do with fewer F-4 squadrons is being interpreted by some military officials as the Pentagon's first step toward tailoring the Marine air force for small wars rather than beef it up for a NATO role.

Marine leaders have been trying to demonstrate that they are powerful enough to fight Soviet forces in Europe, with a NATO exercise in Turkey late this month the next time they will try to make this point.

Navy Secretary Claytor intends to support the Marines' appeal to Brown to restore Harrier money. Claytor is emerging as the Pentagon's leading advocate of proceeding full speed ahead of V/STOL.

Claytor and his Navy allies also are trying to get Brown to restore the cut in made in the Navy's five-year V/STOL research budget.The Navy wants $1.2 billion. Brown so far has approved $550 million.

As the battle of Marine and Navy aviation budget is joined, these are the main choices as set forth in secret memos: