A closely divided Senate Foreign Relations Committee yesterday decided to vote tomorrow on the latest version of President Carter's plan to sell warplanes to Egypt, Israel and Saudi Arabia.

Some administration officials had hoped for a vote today against a resolution disapproving the three proposed warplane sales, but sources in the committee said the members wanted more time before voting.

Several sources said the vote would be very close. There was evidence that Carter could get a majority in the committee tomorrow to vote against disapproval - and hence for the sale - but this could not be confirmed.

Informed sources said Sen. Frank Church (D-Idaho), the ranking Democrat on the committee and previously an outspoken opponent of the sales, had accepted the latest administration compromise and would support it.

That compromise was outlined to Church and other Senate leaders at a breakfast yesterday with Secretary of State Cyrus R. Vance.Vance said Carter was prepared to sell Israel and additional 20 F15 fighter-bombers in the mid-1980s, and to provide a letter to the Foreign Relations Committee with assurances that Saudi Arabia would not arm its F15s as offensive weapons, base them close to Israeli territory or add to them with equipment or planes from other suppliers.

The administration proposes to include these assurances in a letter signed by Harold Brown, the secretary of defenee.

Senate leaders and administration lobbyists say they are confident that a majority of the full Senate will endorse this compromise and allow all three sales to go into effect. (Under the law, both Houses must vote to disapprove a sale in order to block it).

Until the last few days it appeared certain that the Foreign Relations Committee would vote for a resolution of disapproval, insuring a full floor debate. But the administration's willingness to compromise somewhat, coupled with a general reluctance to permit a showdown floor vote that could humiliate Israel and its friends who have opposed the "package deal" of plane sales, may have swayed a majority of the committee, informed sources said.

Church and perhaps others on the committee want one more closed-door hearing with a senior administration official before the final vote. Church met last night with Deputy Secretary of State Warren M. Christopher to discuss this.

Earlier yesterday Vance, Brown, Paul C. Warnke of the Arms Control and Disarmament Agency and Adm. James L. Holloway testified in favor of the plane sales before the House Committee of International Relations.

The four officials essentially repeated testimony given last week to the Senate Foreign Relations panel, backing the sales as a contribution to stability in the Middle East and the security of all three countries.

This drew a passionate rejoinder from Rep. Benjamin S. Rosenthal (D-N.Y.): "We have virtually destroyed the good faith and confidence the Israelis had in our ability to be a first-class (arms) supplier and a first-class friend," by tying the sale of planes to Israel to sales to Egypt and Saudi Arabia, potentially Israel's enemies in a future Mideast conflict.

Rosenthal characterized the administration plan as "weapons for peace," and said Saudi Arabia "probably needs a code of criminal procedure before it needs more airplanes." He was critical of a policy that put the interest of a nondemocratic monarchy (Saudi Arabia) on an equal footing with those of a democratic ally (Israel).

Rosenthal is one of a large bloc of House Members on the International Relations Committee who is expected to vote against the arms sales in that body. A majority of the panel has already cosponsored a resolution of disapproval of the sales, though the administration hopes some of those who signed it might still change their minds.

The House leadership is reliably said to want to avoid a floor vote on the sale, to allow members to avoid the need to take a position on such a divisive issue.

Administration plans to reveal publicly its new compromise proposal yesterday were abandoned when it became clear that several key senators wanted more time to study it. So the administration gave the Senate committee a proposed draft of the letter from Brown describing the compromise.