Negotiations between the United States and the United Kingdom aimed at resolving air policy differences have made little headway, a top Federal Transportation official disclosed yesterday.

Without an agreement in place by June 22, flights between the two countries might be disrupted.

In remarks to the annual meeting of the American Institute of Aeronautics and Astronautics, Deputy Secretary of Transportation John W. Barnum also urged that international aviation matters generally - and these negotiations in particular - be given a higher priority by the U.S. goverment than now is the case.

The two nations began negotiations in September to work out an agreement authorizing air services between the two countries. Last June, the British government gave the U.S. notice that it wished to terminate the 30-year-old Bermuda Air Transport Agreement which now governs air transportation between the U.S. and Britain. Under the agreement, the date of termination is one year after either country gives notice.

Generally, the British feel that their carriers are not earning enough money on their transatlantic routes - mostly because they are carrying only one-third of the traffic - and they are seeking an agreement under which they would be entitled to half the traffic.

The United States position is that U.S. and U.K. carriers are entitled to equal opportunity to the passengers, but that the free market should determine which carriers passengers choose. "We believe that . . . the narket should not arbitrarily be divided into preordained shares between the United States and the foreign country concerned," Barnum said.

Although he declined to get into the substance of the negotiations, Barnum said "the blunt fact of the matter is the British and we are far apart in terms of what a new agreement should provide, and the discussions that have been held in London and in Washington to date have done little except to make it clear that we are indeed far apart."

Barnum urged that the negotiations be conducted by someone appointed by the President as a special representative at the ambassadorial level whose principal, if not exclusive, duty for the next six months would be preparing for and conducting the negotiations. "These negotiations are terribly important to the future direction of our international aviation," he said.

"The United Kingdom is our oldest bilateral partner, and the outcome of our negotiations can be expected to have a profound effect on future bilateral agreements with other countries."

Barnum warned that in general the U.S. government needed "to get its act together better" in representing American interests in international aviation matters by sorting out the roles to be played by the Civil Aeronautics Board and the president, and in the executive branch the relative roles of the White House, the Departments of State, Justice, Commerce, Transportation and the Office of Management and Budget.