Israeli Defense Minister Ezer Weizman flew home today leaving Egyptian officials convinced that a Middle East peace agreement is now within reach.

In substance and in atmospherics, the rapidly unfolding events appear to be moving quickly toward a dramatic announcement when Israeli Prime Minister Menahem Begin and Egyptian President Anwar Sadat meet on Sunday.

Authoritative Egyptian sources said Weizman's two meetings with Sadat and his extensive talks with the minister of war, Gen. Mohamed Gamasy, had made it possible to anticipate an agreement in principle to be announced after the Sadat-Begin talks. Weizman is to return to Egypt before that meeting, the official Middle East News Agency said.

Sadat told a group of Israeli journalists admitted to his rest house in Ismailia that "my people are pushing me" toward peace and "every day there are new implications" of the daring initiative he began with his trip to Jerusalem last month.

He said he and Weizman had talked only in general terms about the principles of a peace settlement but that Gamasy and Weisman had held extensive discussions about troop deployments, borders, and other military aspects ot peace. Sadat said nothing had been made final because Weizman had to report back to Begin.

But according to authoritative Egyptian sources, a peace agreement now seems possible along these outlines: quick Israeli withdrawal from the Sinai; eventual self-rule for the Palestinians of the Gaza Strip and the West Bank of the Jordan, with details still to be worked out; an understanding that some Palestinians driven out ot these territories by war or expelled by Israel will be allowed to return; and acknowledgement by Israel of the principle of Arab sovereignty over all territories captured by Israel in the 1967 war.

Aside from this statment of principle there is nothing in the package for Syria. President Hafez Assad has refused to have anything to do with these negotiations and Egyptian officials say Syria will get nothing until he comes off the sidelines and negotiates directly with Israel.

There are still important gaps between the Israeli and Egyptian positions in conception and in methods of execution, informed Egyptian officials say. As one of them put it, "they have the makings of a cake but they don't have the cake."

Those parts of Begin's peace proposals that have been made public are not enough for Egypt, officials here said, the differences remain after the visit by Weizman.

As expected, the most difficult point appears to be the future of the West Banks. Egyptian sources say Sadat is prepared to accept less than immediate and complete Israeli troop withdrawal, but Israel must give enough in the way of eventual Palestinian self-rule and Arab soverniegty to avoid the appearance that Sadat has negotiated for Egypt lone and sold out the Palestinians.

Referring to two earlier disengagement agreements between Israel and Egypt in which Egypt recovered part of the Sinai without obtaining any Israeli concessions on the other fronts, one informed official said: "What we have now is Sinai III, without any cover, naked. What Sadat wants is Sinai III with enough cover that he can sell it to the other Arabs."

It is highly unlikely that the details of this thorniest of problems can be settled without protracted and difficult negotiations. But the two sides are moving closer together - Israel by showing its willingness to pull back in the West Bank, Egypt by jettisoning the Palestine Liberation Organization.

Israel refuses to negotiate with the PLO in any way or tolerate PLO contol of the West Bank. Sadat has publicly abandoned the PLO as the sole legitimate representative of the Palestinian people and is openly encouraging indigenous West Bank and Gaza politicians who are not part of the PLO to assert themselves.

If an Egyptian-Israeli agreement is reached, Egypt is expected to embark on a campaign to sell it to the rest of the Arab world, especially Saudi Arabia. That is why it is important for the Egyptians to stress that there can be no yielding on the principle of Arab sovereignty over any of the occupied territories and that there is enough for the Palestinians to make it at least an acceptable starting point.

If the implementation of self-rule or autonomy in the Palestinian territories takes some time, even years, Egypt is prepared to accept that, provided that the timetable is worked out in advance.

Gamasy and Weizman are believed to have discussed the technical details of a military pullout from the Sinai by Israel, including the possible demilitarization of Sharm el Sheikh, restrictions on the number of Egyptian troops and perhaps a relocation of the American monitoring station now in the United Nations buffer zone to a new location along the Egyptian-Israeli border.

Weizman, who made a great impression on Sadat when they met in Jerusalem, is said to have asked for arrangements that would give Israel at least 24 hours to mobilize in the event of war, and Egyptian officials expressed understanding of this.

Once again the swirling, unpredictable events overshadowed the formal preparatory peace talks that opened here a week ago. Another plenary session scheduled for today was postponed because the Israeli delegation went to Ismailia to see Weizman.

If things go well at the meeting between Sadat and Begin on Christmas Day, the Egyptians forsee the quick elevation of this conference to the foreign minister level to work out the details of implementation.

The Egyptians would also like to make enough progress over the coming week to be able to bring President Carter into the proceedings when he makes his overseas tour in late December and early January. At the moment no meetings with Carter are scheduled.

The rapport between Weizman and Sadat is a stunning measure of how rapidly things are changing in relations between Israel and Egypt. Until a month ago, Weizman was viewed here as a wild man, a war monger, the man who said before the 1973 war that if the Egyptians tried to cross the Suez Canal they "would take such a trouncing, inside Egypt proper, in their own homes, that the Six Day war would seem like an agreeable memory by comparison."

Now Sadat refers to him as Ezer, and the Egyptians talk sympathetically of the head wound suffered by Weizman's son in the very war Weizman said Egypt could not start. As Weizman left today after meeting Sadat, Samasy and Vice President Hosni Mobarak, Weizman was heard to call out "ok, Hosni, see you Sunday."