The airlift proceeded through the night according to a complex schedule involving thousands of people in Israel and Ethiopia, the three dozen aircraft, and more than 400 buses at both ends.

The bulk of it was carried out during the Jewish Sabbath, sundown Friday to sundown Saturday. But there were no complaints from the religious authorities; Jewish religious law allows and even encourages the violation of Sabbath observance if it is done to save lives. And in this case, the Sabbath actually made the operation easier since all the aircraft and buses used would have been idle.

Israel had placed the whole operation under total military censorship that was lifted only tonight. Even after the rest of the world had learned most of its details from other sources, the Israelis had refused to discuss it because of commitments they had made to both the Ethiopian and United States Governments.

The complex logistics for the flights had been in place for weeks, but it took a letter from President Bush to the new Ethiopian leadership on Thursday to prod officials to allow the Jews to leave all at once, Israeli officials said Friday. Before he fled to exile on Tuesday, President Mengistu Haile Mariam had used the Ethiopian Jews essentially as bargaining chips, seeking to exchange their controlled departure for Israeli arms and perhaps aid from Washington.

Aboard flight No. 9 this morning, on a Boeing 757 with the El Al insignia and Star of David painted over, workers here had covered all the seats and flooring with thick plastic sheeting, to protect them in case any immigrants carried infectious diseases. Five doctors or paramedics were aboard, and said they worried that some of the Ethiopians might carry cholera, malaria or possibly even AIDS.

Following the script, the pilot did not take off from here until a returning plane had landed, just before 1 A.M. Flight 9, like all the others, followed a route over southern Israel to the Gulf of Aqaba, and then over water all the way to the Ethiopian coast and west to Addis Ababa, arriving at about 4:30 A.M. Even at that hour, the city was brightly lit, and the plane had to circle for 10 minutes before landing, because so many other planes from several countries were trying to crowd into the airport to evacuate their people. An Isolated, Weedy Taxiway

After landing, the pilot taxied somewhat tentatively, not sure where he was going and apparently getting little guidance from ground control. Finally he stopped on an isolated taxiway nearly overtaken by uncut weeds on either side. But when the door opened into the darkness, a dozen Israeli immigration and security personnel were standing by outside.