The Egyptian and United States air forces have conducted "joint training exercises" in Egypt recently to test the capability of U.S. warplanes to use bases here, Egypt's defense minister disclosed today.

The purpose of the exercises, Defense Minister Kamal Hassan Ali said, was "to make it easier for the air forces of the United States to cross our skies and to land at our bases where they can get facilities."

The disclosure of the air exercises comes as the United States has been intensifying its redeployment of military strength in the Middle East and South Asia in the wake of the political convulsions in Iran and the Soviet invasion of Afghanistan. Included is a push by the United States to develop a "network" of bases for a rapid deployment force. [Washington sources said Tuesday that two AWACs planes used to spot incoming aircraft, surface ships and to direct the flight of friendly planes have been in Egypt for three weeks, along with a supporting force of 250 Americans, including the pilots and crew. Details on Page A18.]

Ali also disclosed that Egypt is expanding its role in the crisis by beginning to establish training camps for use by Afghan rebels in their struggle against the Soviet troops.

The Egyptian defense minister said American aircraft were involved in the base exercises, which were conducted about two weeks ago at undisclosed Egyptian facilities. Ali declined to say what type of U.S. aircraft were involved or how many in his remarks to reporters during Israeli Prime Minister Menachem Begin's visit here to discuss regional strategic issues with Egyptian President Anwar Sadat.

Sadat and Begin met for nearly two hours this afternoon, beginning their second session of the four-day visit in a hotel room and then moving to a balcony and, finally to the edge of a swimming pool to the Oberoi Hotel, situated on Elephantine Island in the Nile River.

While talking alone by the pool for more than an hour, Begin and Sadat bent over a large map of the Middle East and talked animatedly, although aides declined to reveal what they said, pending a scheduled press conference Thursday after a third and final session.

Dan Pattir, Begin's press secretary, said the talks followed "the regional thrust" that began in their meeting in Alexandria, Egypt early last summer and intensified as events in Iran and elsewhere in the area worsened.

While Pattir said the two leaders also discussed bilateral issues such as the normalization of relations between Egypt and Israel and proposed autonomy for Palestinians in the West Bank and Gaza Strip, it was clear that instability in the region was the main focus of today's talk.

Pattir declined to say whether Begin and Sadat discussed possible joint military cooperation between Egypt and Isreal, although Ali told reporters he felt that would be unlikely at the moment.

Ali said that after a comprehensive peace is reached in the Middle East and after the Palestinian issue is resolved, "perhaps all countries in the area" could "join in the fight against outside aggression."

U.S. ambassador to Egypt Alfred Atherton visited Aswan yesterday and reportedly met with Sadat to give him a note concerning the situation in the region. However, those reports could not be independently confirmed and Israeli and Egyptian officials would not comment.

In explaining the air force exercises, Ali said, "The main purpose was to test the feasibility of facilities." When asked where the air operations were held, he replied "somewhere in our country."

While he was no more specific than saying the exercises occurred about two weeks ago, Ali stressed they were held after the invasion of Afghanistan but "in reference to Iran."

When asked if the exercises involved establishing flight routes, communications and other measures that require joint cooperation prior to deploying aircraft here, Ali answered "yes, something like that."

Egypt has said before that it was willing to make training camps available to Afghan rebels, but today's disclosure by Ali was the first indication that bases were already prepared for the Afghans. It was not clear when -- or if -- the Moslem rebels would begin arriving in Egypt, or exactly how they would get there.

"We have prepared for receiving people of Afghanistan who want to share in the fight . . . ," he said. "Camps have been opened for this and are ready how to receive anyone. We'll do everything to help the people of Afghanistan to help themselves."