Greece's air and naval units joined the armed forces of five other NATO countries including Turkey in joint military maneuvers in the Aegean sea today.

It is the first such Greek participation since August 1974, when Athens withdrew from the military wing of NATO after another NATO member, Turkey, invaded Cyprus, and Greece faulted NATO for refusing to act.

Since then Premier Constantine Karamanlis' government has been "walking a tightrope," according to a Western source. It has attempted to forge a "special relationship" with the alliance to cover the country's military requirements, yet not incite a volatile Greek public that, after Cyprus and seven years of dictatorship, can be easily rallied against NATO and the United States.

However, Greece's infantry will not take part in the conclusion of the exercises next week.This will involve U.S., British and Turkish forces in an amphibios landing maneuver in the Turkish part of Thrace.

Minister of Defense Evangelos Avcroff insisted that Greece's participation in the Aegean maneuvers does not portend an imminent return to the alliance's military arm, and that until there is a solution to the Cyprus crisis. Greece would persist in its demands for a "special status" with its Western allies.

But political observers in Athens suggest that Karamanlis has been leading Greece back into the alliance and that today's maneuvers in the Aegean are a step toward restoring stability to the alliance's southern flank.

Greece's present ill-defined membership status has caused a number of deficiencies in NATO's southern flank, mainly a disruption of the early warning system, which, though still functioning in this country, is no longer integrated into the general command.

There has also been a disruption of communications between Italy. Turkey and Greece, and Athens has refused to allow NATO maneuvers to take place in Greece.

"During the past 18 months, the Greek government has been swinging firmly back to NATO," one Western military expert said. "She's signed a new defense agreement with the Americans, she's participating in the present exercise, Karamanlis has consistently emphasized before Parliament that Greece belongs to Europe and the West."

"He's pinned the country's political future to the Common Market," the source continued, "and NATO and the Common Market tend to go hand in hand. This all appears to be part of a campaign to prepare public opinion for a return to the alliance . . . When? Only Karamanlis can say."

Aware of local sensibilities, NATO manipulated its command structure to allow Greek participation in the current exercise.Instead of being directed from NATO's headquarters in Izmir, Turkey, with a Turkish admiral in command, jurisdiction was switched to NATO's Mediterranean regional headquarters in Naples, and a British admiral took command.

A NATO official said this "is probably the most important reason behind Greece's participation today. If they had not participated, the Turks would have taken over. And, from the Greek point of view, it would have been inadmissible for a Turkish admiral to command a force in the Aegean, an area which the Greeks are guarding as a Greek sea."

"There is also an awareness, and a growing impatience within the Greek officer corps," he said. "They know that the Greek armed forces are fully dependent upon NATO and that by refusing to participate in maneuvers, Greece has no yardstick and will loose her expertise."

"The biggest stumbling block," said one NATO official, "is that Greece wants to maintain her troops under national command. . . . What she wants, in effect, is for the alliance to underwrite the positioning of her forces against Turkey, another NATO ally. This is hardly in keeping with the terms of a military pact."