An Israeli team of experts was given a nine-hour flight in an AWACS Monday as part of the Reagan administration's effort to win approval for its controversial proposal to sell five of the sophisticated radar planes to Saudi Arabia.

At the same time State Department and Air Force officials were formally notifying Congress of the administration's desire to proceed with the sale, Israeli technical and military experts were making a round trip from Tinker Air Force Base near Oklahoma City to Langley Air Force Base in Hampton, Va., aboard an AWACS manned by U.S. Air Force personnel.

An Israeli Embassy spokesman said yesterday that the flight followed briefings at the Pentagon Friday for the five-member Israeli team, which was given detailed information about what an AWACS can and cannot do. An AWACS, for Airborne Warning and Control System, is a modified Boeing 707 crammed with electronic gear that can identify and track hundreds of aircraft and guide fighter planes into battle.

"The Air Force did its best to help the team, from what I understand," the Israeli spokesman said. "This is part of the campaign to convince the Israelis to reduce their opposition to the sale."

An Air Force spokesman said the purpose of the round-trip flight was to acquaint Israeli technical and military experts "with the capabilities and limitations" of the radar planes.

Israel has charged that the AWACS' ability to monitor aircraft movements would greatly increase that nation's vulnerability in a time of renewed crisis with its Arab enemies. The Reagan administration argues that the sale is necessary to help protect Saudi oilfields, which produce 63 percent of Persian Gulf oil and to help forge a better U.S.-Saudi relationship. U.S. officials say that Israel would not be endangered by the AWACS sale.

The sale will be made unless both house of Congress vote against it within 50 days of their Sept. 9 return from recess. A majority of both chambers has expressed concern over the proposed sale, but both sides predict a close fight. Senate Majority Leader Howard H. Baker Jr. (R-Tenn.) predicted yesterday that the Senate would approve the sale.