The driving force behind the Carter administration's Mideast arms policy is to give nations there "a sense of sufficient security" to negotiate a peace. Defense Secretary Harold Brown said yesterday.

Arm sales, he said, "by themselves" will not bring peace and "are helpful only insofar as" they foster the sense of security needed to bring potential combatants to the peace table.

The defense secretary told a Pentagon news conference that the proposed sales of U.S. warplanes to Israel, Egypt and Saudi Arabia address their legitimate security needs.

Israeli officials disagree and have concentrated their fire on the proposed sale of 60 F15 fighters to Saudi Arabia.

Brown, who met with Israeli Defense Minister Ezer Weizman yesterday and Thursday, said Saudi Arabia needs "air defense," partly to combat a threat from Iraqis who "are very heavily armed by the Soviets with the most modern ground and air equipment," including "1,300 tanks and some hundreds of aircraft."

Weizman, in a press conference following Brown's, said he felt reassured after meeting with President Carter yesterday about the U.S. commitment to Israel's security.

The Israeli defense minister characterized the political atmosphere between the United States and his country as "very tense" but said it was improving like the Washington weather.

Weizman answered "yes" when asked if any specific decisions had been made by the Carter administration on Israel's arms requests, but he would not disclose them.

"We want our 90 and we want more," said Weizman in referring to the 75 F16 and 15 F15 warplanes Israel would get in the proposed Carter package. He said at another point in his press conference that Israel hopes to get 175 more U.S. warplanes between now and 1983, but did not specific what types were on the shopping list.

Although declaring that, "packaging" the aircraft for Israel, Egypt and Saudi Arabia "was wrong," Weisman said the military help the United States has given Israel over the last four years had been "above and beyond whatever I thought" would be provoked.

Brown, in his Pentagon press conference, discussed a number of subjects besides Midwest arms, including:

Horn of Africa. "We would hope and expect" that Cuban and Soviet presence in Ethiopia will be reduced and eventually eliminated now that Somali troops have withdrawn from Ethiopia.

"We don't know that that is going to happen, nor do we know what may happen in the future in Rhodesia.

"The pattern that we have seen for Cuban and Soviet involvement in the Horn of Africa is a very disquieting one and would be even more so if it were extended elsewhere in Africa."

Neutron bomb. Brown confirmed that the Carter administration has discussed the possibility of putting "some limitations" on this weapon in exchange for the Soviets calling off deploying "some substantial" weapon which he did not identify.

Soviet pilots in Cuba. The defense secretary said "there have been Soviet pilots flying Cuban aircraft in Cuba on and off for a long time, and I would say there has been no substantial change in the pattern . . ."