The Senate Foreign Relations Committee set the stage yesterday for action on President Carter's Middle East warplane sales package in a deeply divided Congress where, at least as of yesterday, the administration showed strong prospects of prevailing.

The committee scheduled hearings on the plan to sell advanced military aircraft to Egypt, Israel and Saudi Arabia after making a proforma request to the president to withdraw his proposal for 30 to 90 days so a Senate subcommittee could travel to the Middle East for an on-the-spot investigation.

The requested delay, made largely to please Sen. John J. Sparkman (D-Ala.), the committee's chairman, appeared unlikely to win presidential acquiescence.

Informed sources in the administration and in Congress said yesterday that opponents of the proposed plane sales - led by the pro-Israeli lobby - apparently do not have sufficient votes in the House and the Senate to block the transactions, though they said the mood could change before a final vote.

A majority of the Foreign Relations Committee membership appears to oppose the sale of advanced F15s to Saudi Arabia at this time.

Sen. William Proxmire (D-Wis.) has introduced resolutions of disapproval to kill the warplane sales to all three countries and under the complexation sales act, the Foreign Relations Committee must act on these requests within 10 days from last Friday the vote on resolutions of disapproval that could block one or more of the sales, if carried by both houses.

Senate leaders are convinced that a majority of senators would vote against any resolution of disapproval, even if one is approved by the Foreign Relations Committee.

Administration head-counters have made the same calculation. The administration also thinks the House could reject a resolution of disapproval, and got a boost on this core yesterday when Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass) said he would work for the administration in the coming floor fight.

O'Neill told reporters that, on the basis of a briefing he received from Secretary of State Cyrus R. Vance, he now believed the so-called package deal of arms sales was in the best interest of the United Sates and of peace in the Middle East.

Last week O'Neill said he doubted the administration had the votes to carry the arms sales through Congress, but he did not repeat porgnosis yesterday. He did question whether a resolution of disapproval could be blocked in the House International Relations Committee, where opinion is closely divided.

However, administration lobbyists and committee chairman Clement J. Zablocki (D-Wis.) believe that panel may reject a resolution of disapproval. The House committee will open its hearings on the sales next week.

[Just before the Senate committee action, Israeli Prime Minister Menchem Begin and President Carter softened the sharp edges of their discord over the overall path to Arab Israeli peace, without resolving the underlying differences.]

[In all emotional ceremony on the South Lawn of the White House celebrating the 30th anniversary of the conflict-born state of Israel, Carter landed Israel and simultaneously urged upon it greater flexibility in peacemaking.]

The mood in Congress toward the warplane sales has apparently changed substantially since last week, when Carter agreed to stop calling the sales a "packates" whose elements all depend on one another. Previously, the administration had insisted that unless Congress approved all three elements of the package, note of them would go through.

Some members in both bodies apparently resented this as an intrusion in congressional prenogtives, since the law provides that each proposed arms sale must be considered by Congress independently. So the administration changed its tune slightly, affirming that it, too, wanted Congress to consider each one separately.

This is not a substantive change apparently, and members of Congress still expect Carter to withdraw the proposed sale of planes to Israel if the sale to Saudi Arabia or Egypt is blocked.

Israel and its supporters here have opposed the sale of 60 F15s to Saudi Arabia as a potential threat to Israel's security and an unnecessary escalation of the Mideast arms race. Israel has also expressed dismay at the idea that a sale of planes to it should be tied to the sale of planes to its potential enemies.

Begin raised the issue with Carter yesterday, White House sources said, again expressing Israel's view that the historic U.S. commitment ot Israeli security should have a special status in American eyes. But Begin did not move away from Israel's stated position that it wants the planes that it would buy under the planes that it would buy under the package deal, whether or not the Saudis and Egyptians get theirs.

Some members of the pro-Israeli lobby here are now suggesting that Congress should dispprove the Saudi sale, and let the administration then decide what to do about the other two.

But the administration is arguing strenuously that the sale of F15s to Saudi Arabia is crucial if the U.S. is to continue to use the dollar as their principal currency. These arguments have been received sympathetically by many House and Senate members.

To prevail, opponents of the arms sales have to win four votes - in each of the committees, and on each floor. If the administration wins any one of the four, the sales go through.