The Navy, now that it has changed course from giant to medium-sized carriers, intends to spend $1 billion to design new planes to go with them. But the big-carrier advocates in the House are fighting this change, too.

The House next week is scheduled to choose between its Armed Services Committee, which cut out the money for new aircraft to go with "midi" carriers, and Navy leaders who insist they must develop a new generation of aircraft that could take off and land on a short space of carrier deck.

Such aircraft are called V/STOL, for vertical or short takeoff and landing. Building a better V/STOL is vital to the Navy's plan for a mixture of large Nimitz class and midi carriers at sea in the 1980s.

Navy dealers already have told aerospace executives that they are serious about changing the course of carrier aviation. They consider the $1 billion as earnest money, which they intend to use for buying V/STOL designs from industry and then to transform the best of them into flying test models. The test planes would be subject to a flying competition before the Navy picks its V/STOL for the future.

Although the Marine Corps already is flying a V/STOL called the Harrier, it does not fill the Navy's hopes for a plane that could not only take off in a short distance but could also carry a heavy load of bombs and rockets to battlefields far inland from a carrier.

Adm. James L. Holloway, Chief of Naval Operations, is taking a personal role in what he calls the "tryansition" from the giant carriers to a mixture of big and medium-sized ones. Although the first "midi" carrier is expected to be one of about 50,000 tons, or roughly half the size of the $2 billion Nimitz, Holloway also envisions future "mini" carriers of about 25,000 tons.

Holloway and other Navy leaders ran into opposition when they sought to switch to the midi instead of building a fourth Nimitz class carrier. But the majority of the House and Senate went along with the change in approving President Carter's revised defense budget for fiscal 1977.

Now Holloway and his allies are running into fresh opposition as they try to get Congress to approve money for developing the V/STOL to go with the smaller carriers.The House Armed Services Committee, in cutting $28 million from the Navy's request for $32.5 million to develop a new generation plane for the smaller carriers, complained: "The Navy has not submitted a plan for the V/STOL aircraft program that describes sound rationale and system objectives."

The committee took a dim view of the prospects for a breakthrough in V/STOL technology, stating that "hundreds of millions of dollars already have been spent by Britain and the United States without getting planes that can compare with present-day fighter-bombers that operate from large carriers.

Today's planes could land on medium-sized carriers of between 50,000 and 60,000 tons, but not on the mini carriers of about 25,00 tons that the Navy hopes to build if improved V/STOL aircraft are developed.