At Kennedy Airport, the first Americans to retaliate for the seizure of the U.S. Embassy in Iran are itching for more U.S. action.

They applaud President Carter's decision to freeze all Iranian assests, but they want more. Impose a total blockade? Deport all Iranian students? Assassinate Ayatollah Ruhollah Khomeini? Send the Marines? Right on! Says Local 504.

Local 504 of the Transport Workers Union took the first anti-Iranian action following the Nov. 4 embassy seizure when it refused last week to service Iran Air planes at Kennedy Airport. Its action ide to the diversion of one plane to Montreal and the subsequent cancellation of all Iran Air Trans Atlantic flights. Now the 504 workers follow events in Tehran with a passionate interest and a strong desire to see Iran -- and Iranians -- punished.

"For once public opinion is very strong. It's unusual to see people so nationalistic," shop steward Jack Buonomo said in the cafeteria at Kennedy Airport where the workers relax.

Local 504 is proud that it was the first to act and pleased that most Americans share the members' anger and determination not to give in to Iran. Local 504 didn't get such united sympathy when it demonstrated in support of the war in Vietman.

The embassy seizure and Vietnam are linked for Sol Scope, a mechanic, and other union members. Iran, like Vietnam, is another small country trying to push the United States around, Scope said. "How can a small nation like Iran destroy us?The U.S. is a world power," Scope said.

Why didn't President Carter take a stand? Why did it have to be a labor union to act first?" Scope asks.

Other members of Local 504 are more approving of the president, but listening to about 20 of them talk in the cafeteria leaves no question that they would support Carter if he chose stronger action.

"I think he should cut off the wheat," Mike Morrissey, a fleet serviceman, said. "Private industry should get in back of the president and there should be a total blackade."

Joseph Sharp, who cleans jetliners, agreed. "Let them eat oil," he said Sharp also had been urging, before Carter acted, that all Iranian assets in the United States be frozen. As for Iranian students, Sharp would like to see them all rounded up and shipped out.

Khomeini? "He's a nut," Buonomo said. He proposed that the United States assassinate Khomeini, but others objected that Iran has lots of nuts and another ayatolah just as crazy might well take over. Buonomo argued that the country's army would seize power and Iran would calm down.

It is likely that not since the end of the U.S. combat role in Vietnam have Local 504's 6,000 members -- and many other Americans -- been so emotionally involved in an event taking place overseas. Even if they hadn't been asked the questions in the cafeteria about Iran, many of the unionists would have been discussing it among themselves.

On the principal Iranian demand -- that the United States hand over deposed Shah Mohammad Reza Pahlavi -- the workers make clear that the Iranians miscalculated if they thought American public opinion would presure Carter to push the shah from his New York hospital bed, where he is being treated for cancer and bile ducts being treated for cancer and bile duct problems, into the hands of his enemies.

"The United States has always been a sanctuary. We can't give up the shah or anyone else," Mel Brackett, president of Local 504, said. Bracket says that the United States cannot deport all the Iranian students for the same reason, but many of his union members disagree with him.

When the embassy was seized, Brackett said, he received more than 100 telephone calls from union members who wanted to do something. Many urged him to hire buses and lead a protesting group to Washington or to picket the Iranian mission in New York, but Brackett said the boycott of the planes was enough for now.

If the drama at the embassy ends in calamity, Local 504 is inclined to make the boycott permanent.

"If any of those hostages in harmed, we'll boycott Iran Air until hell freezes over," Brackett said. He and other local officials said they would ask the AFL-CIO to extend the JFK boycott to other airports serviced by other unions.

Anthony West, a cleaner, wants U.S. military intervention in Tehran.

Though gasoline lines, higher gasoline or heating oil prices and the need to conserve energy might result from a military thrust into Iran, West and many others in the cafeteria of the Pan Am terminal, are pepared to put up with those consequences.

The price Local 504's members don't want to pay is further humiliation of the United States by a small country.