President Carter, in a series of decisions with major diplomatic and domestic consequences, has decided to sell nearly $5 billion in advanced warplanes to Israel, Egypt and Saudi Arabia.

The sales would be a stepup in United States military support for Egypt and Saudi Arabia, while providing Israel with less than it asked.

Secretary of State Cyrus R. Vance, who announced the proposed sale yesterday, defended them as "consistent with the overriding objective of a just and lasting peace" in the Middle East and suggested that they would help to encourage flexibility in the current Egyptian-Israeli negotiations.

Vance also maintained that the aircraft, most of which would be supplied in the 1980s, would not alter "the basic military balance" in the region.

A battle over the decisions is certain in Congress, which can block arms sales by majority vote of both chambers. Ten of the 15 members of the Senate Foreign Relations Committee, which will pass on the issue, warned Vance three weeks ago against going ahead with the sale of highly sophisticated fighters to Saudi Arabia at this time. Rep. Lester L. Wolff (D-N.Y.) announced yesterday he will move to block the Saudi sale in the House of Representatives.

Sharp criticism from Capitol Hill was also heard yesterday of the proposed sale to Egypt of medium-range fighter-bombers, the first "lethal" military equipment to be supplied to that country by the United States.

The proposed sales, as announced by Vance, are:

For Israel, $400 million for an additional 15 sophisticated F15 fighter planes to go with the 25 already on order. Israel would also get 75 modern F16 fighter-bombers for $1.5 billion.

For Egypt, 50 F5E fighter-bombers for $400 million. The FSE is a highly maneuverable but short-range plane.

For Saudi Arabia, a giant jump into modern warplanes through the purchse of 60 F15s for $2.5 billion.

The Carter administration is gambling that $4.8 billion in modern warplanes would make peace more likely, despite the risk that these new weapons would make any new Arab-Israeli conflict bloodier and more extensive than the previous four wars since 1948.

Vance said in a television interview last night that Israel and Egypt were informed of the decisions Monday and that both had indicated displeasure. Israel "made no bones in advance they didn't like the decision," Vance said on the Public Broadcasting Service's MacNeil-Lehrer Report. Vance described Egypt as "very unhappy they were not getting everything they asked for."

Asked why arms decisions of farreaching military, diplomatic and political consequences were taken at a time of uncertainly in the delicate Mideast negotiations, high level State Department official replied that the countries involved were pressing for prompt decisions. "We thought it was important to bite the bullet now," he said.

Carter, who strongly criticized U.S. arms sales and the Mideast arms race in particular during the 1976 presidential campaign, is believed to have made personal commitments recently to leaders of all three countries that warplanes would be supplied. U.S. officials maintain that the basic commitments to the Israeli and Saudi sales go back to the Ford administration, however.

In justification of the sales, which would occur over a period of about three years and be within Carter's arms export ceilings, Vance declared:

"Our commitment to Israel's security has been and remains firm. Israel must have full confidence in its ability to assure its own defense."

Administration officials justified the cutback in the F16s to be supplied to Israel - from a reported request of 150 to a proposed sale 75 - on financial and military grounds. However, Israeli supporters on Capitol Hill immediately voiced suspicion that a form of diplomatic pressure was involved.

"Egypt, too, must have resonable assurance of its ability to defend itself if it is to continue the peace negotiations with confidence," Vance said, adding that Egypt lost its major arms supplier by breaking its previous close alliance with the Soviet Union.

There is no doubt that the announcement was intended as a major display of support for the peace initiative of Egyptian President Anwar Sadat, who asked outspokenly for arms support during his recent trip to Washington. The congressional reaction is likely to be a test of Sadat's political support in the United States.

As for the sale to Saudi Arabia, Vance said that nation "is of immense importance in promoting a course of moderation" in Middle East peace-making and in worldwide petroleum and financial policy. "The Saudi government has a legitimate requirement to modernize its very limited air defense," Vance said.

The F15 slated for Israel and Saudi Arabia and the F16 scheduled to go only to Israel have enough range to fly between 600 and 900 miles from their home bases and return, depending on how much extra fuel and armaments they carry.

This would mean that Israel and Saudi Arabia could fly deep into one another's territory - between Tel Aviv and Mecca, for example. By using aerial tankers to refuel in flight, the F15s could strike deep into Africa as well as the Mideast.

In contrast, the F5E Carter wants to sell to Egypt is a comparativey shortranged fighter and bomber, capable of flying between 250 to 300 miles from its bases. U.S. Air Force specialists believe it is no match for either the F15 or the F16.

Senior administration officials noted that Sadat has said no intention of going to war again with israel. They said the F5E might help protect Egypt from its Soviet-backed neighbor, Libya.

Originally, the Israelis talked about buying 50 F16s from the manufacturer, General Dynamics of Fort Worth, and building 200 more of them in Israel.

But the Carter administration was reluctant to approve coproduction, partly for fear that F16 technology would be used in other planes Israel built and offered to sell abroad, with Latin America one likely market.

Israel, having failed to win home production cut the orde on its wish list to 150 F16s. State, for the moment anyhow, has decided to limit the order to 75. CAPTION: Map, Strike Ranges of U.S. Jets in Mideast Have Grown Since '66

The strike range of U.S. planes sent to the Mideast has increased markedly since Israel ordered its first American jet fighter-bomber in 1966, the Navy A4 Skyhawk. Israeli aerial tankers added since then put the older A4 and F4E Phantom fighter-bombers in range of Libya and Saudi Arabia, as the map shows.; Picture 1, The Carter administration announced yesterday that it proposes to supply Saudi Arabia with 60 F15 long-range fighters and Israel with an additional 15 of them; Picture 2, Israel would also get 75 F16 fighter-bombers; Picture 3, and Egypt would get 50 F5E fighter-bombers, The F15 and F16 have strike ranges of between 600 and 900 miles without refueling, depending on how much extra fuel and what kind of armaments they carry, while the F5E has a combat radius of between 250 and 300 miles.