Negotiations over a small U.S. training and technical team that would be part of the proposed sale of American combat jets to Egypt are beginning to touch sensitive political nerves here, with implications that could bear on congressional approval of the arms package.

The Egyptians, whose memories are still fresh with the heavy-handed presence of 20,000 Russian advisers before President Anwar Sadat's break with Moscow's 1972, are understood to want to keep the American team as small as possible.

Moreover, the Cairo government is aware of the political implications in Washington of the prospect of even a token U.S. military presence here, as Congress prepares to consider the package sale.

A congressional veto of the deal would be a serious setback for Egypt, not just politically but militarily. Egypt's need for the 50 F5E planes that the Carter administration hopes to deliver is apparently even greater than was previously understood because attempts to acquire the advanced Mirage F1 from France have fallen through, military sources here report.

Reports published in Europe and the United States since 1975 saying that France had agreed to sell 44 of these planes to Egypt are not true and probably never were, military sources say, and an Egyptian request to build the Mirage here under license has been quietly shelved. As a result, Egypt has nothing other than the F5Es lined up to bolster its deteriorating fleet of combat aircraft.

The Carter administration's all-or-nothing package of jet sales to Egypt, Saudi Arabia and Israel is expected to be submitted to Congress later this week. Egypt would get 50 F5Es, Saudi Arabia would get F16s and 15 F 15s. The planes earmarked for Egypt are the least sophisticated in the package, relatively short-range fighter-bombers designed for defensive use by developing countries.

It would be the first sale of American combat aircraft to Egypt, which for two decades was equipped almost exclusively by the Soviet Union. The heart of Egypt's fleet of some 470 combat planes is the aging MIG 21, which Egypt has had trouble overhauling and refitting since Sadat's break with Moscow.

Sadat wanted more than 50 U.S. planes and something more sophisticated than the F5 but had to settle for what was politically realistic.

Military analysts here believe that Israel's opposition to the sale of these jets to Egypt is based less on the fighting capabilities of the F5, which pose little threat to the Israelis than on the likelihood that the United states for the first time would establish a technical assistance and training relationship with the biggest and most powerful of the Arab front-line states.

Military experts believe Egypt could get by with relatively little help in putting the F5 into service, learning to fly it and keeping it in operation.

Some Egyptian pilots have already been trained to fly the F5 in Saudi Arabia, according to Western sources. Egypt has extensive facilities for maintaining combat jets.

Qualified sources say current discussions indicate that about 35 Americans would have to be stationed here at least temporarily, some to assist with such technical tasks as setting up a parts inventory but most to provide "tactical help" teaching the Egyptians what the Americans know about fighting a war in the air with this plane.

In other countries where the United States has such missions, including Saudi Arabia, the American team includes military personnel as well as civilians who work for the plane manufacturer. A similar arrangement is contemplated here, informed sources said, but details are far from complete.

Experienced analysts of such arrangements, said, however, that they doubt whether the Egyptians would want even the 35-member mission under discussion.The Egyptians are extremely secretive about the working of their armed forces and sensitive to any suggestion of foreign influence, especially since their experience with Soviet Advisers.

Egypt has been trying for the past three years, since its break with the Soviet Union, to diversify its sources of weaponry. THe repored deal with France for the Mirage F1 was said to be a part of that program. Egypt did acquire an estimated 38 Mirage III jets but the F1, a high-altitude, all-weather, supersonic, multipurpose plane, is much more sophisticated.

A French agreement to sell Egypt 44 of the F1s was first reported in 1975. However, French and other Western sources here say there never was any such deal and Egypt is not getting the F1.

It also appears that an Egyptian request for permission to build the F1 under license here has fallen through, and reports in the Cairo press that Egypt is now dickering for the purchase of the latest Mirage model, the 2000, are dismissed as premature by Western military analysts since that plane only made its first test flight last month and is years away from full production.

For the Egyptians, that leaves virtually no new combat jets on the horizon except for the Northrop F5 deal proposed by President Carter. It is seen here as a military necessity for Sadat as he tries to keep his armed forces happy and capable, as well as a political gesture to show that the United States appreciates his peace initative.