Beirut — Throughout the Arab world, the Middle East plan set out by President Reagan is receiving a cautious airing.
Some Arabs, like the academician who said it was about as appealing as ''an unfrozen TV dinner,'' view the Reagan plan with obvious disgust. Iran's non-Arab leader, Ayatollah Khomeini, has threatened his neighbors with possible retribution if they accept the plan.
But Arabs generally, including key elements of the Palestinian Liberation Organization, appear to be feeling their way cautiously on the topic, which could be bound for a showdown at the Arab League summit in Fez, Morocco.
That caution may just be stage fright that this summit will be as disastrous for Arab unity as the last one, which collapsed in November after a mere five hours in conference.
That Arab summit made the idea of ''Arab unity'' seem preposterous. It came to pieces over Saudi Arabia's plan for Middle East peace that went far beyond Reagan's in terms of satisfying Arab demands.
This week's meeting, technically a resumption of the failed one, comes at an even more critical time with Israel occupying part of Lebanon. It is the first time Arab leaders will be face-to-face with Yasser Arafat, who has said repeatedly they failed the PLO miserably during Israel's invasion.
Syria looks set to be the spoiler again. The last meeting was doomed when Syrian President Hafez Assad decided to boycott because the Saudi plan was on the agenda.
Although Syria has withheld official comment, sources in Damascus said President Assad asserted his nation would lead ''the rejection front'' at the summit. He was said to have pledged to spearhead opposition to Mr. Reagan's proposals during a more than four-hour meeting with the PLO leaders now living in his capital.
Notably, Mr. Arafat was not present while the others met with Assad.
The radicals in the PLO pronounced their veto of it while Arafat sidestepped comment. The chief ''hole'' in the American initiative is that it rules out an independent Palestinian state. The PLO split is a replay of its division on the Saudi plan presented at the November summit.
Has the PLO splintered as a result of Lebanon? Or is this a typical Arafatesque tactic to please both the radical and moderate Arabs in order to maximize the PLO's political gains?
In pre-war days, one could comfortably choose the latter. But the Israeli invasion and the resulting exodus of the PLO has shaken up the Arab world political puzzle. It will undoubtedly take some time for the pieces to find new niches.
Jordan's equally cautious reaction to President Reagan's initiative was normal for the moderate King Hussein.
An official, quoted by the state-run Jordanian news agency Petra, however, cautioned that the Hashemite Kingdom's final stance would be based on the resolutions of the 1974 Arab League summit.
Jordan and the Arabs declared the PLO the official representative of the Palestinian people. But the Reagan proposals speak of the West Bank and Gaza Strip as being tied directly to Jordan, which directly contradicts the 1974 summit.
King Hussein's position in the Arab leadership hasn't been strong enough to fly in the face of that. But there have been reports in recent months that Arafat had agreed with King Hussein that the monarch should negotiate the return of the West Bank and Gaza and later the final jurisdiction of them would be decided ''within the Arab family.''
Saudi Arabia has been making contacts, especially among her Gulf neighbors, to discuss the Reagan plan. The Gulf nations are holding to the line that their final opinion will echo those of Jordan and the PLO.
Conservative Arabs say the Arabs must pursue the American solution because for once the US is focusing on the Palestinian problem as something other than a question of troublesome refugees.
After what is considered US mishandling of the Israeli invasion, the fact that the Americans are saying no more settlements and questioning the status of Jerusalem is a breakthrough, a political source in the Gulf said.