The New York Yankees are fueding again, but after a shouting match between Manager Billy Martin and catcher Thurman Munson, it remains unclear as to who is upset with whom.

Manager and catcher had fiery words at the airliner carrying the team here landed at O'Hare airport early yesterday morning. They were said to be close to exchanging blows before being separated by other team members.

"It was just a misunderstanding," said Martin. "It had nothing to do with Thurman - it was about someone else."

Versions as to who that "someone else" differed. One report was that Martin was actually upset with center fielder Mickey Rivers, who the manager felt had not hustled sufficiently in getting over to Amos Otis' ninth-inning blow to right-center field Sunday that eluded right fielder Reggie Jackson and gave Kansas City a 10-9 victory.

Another version had Munson responding to alleged comments by Coach Dick Howser that the catcher had given less than his best effort on a missed tag at home plate earlier in the game.

"I play hard all the time," Munson was reported to have said to Martin. "I can't believe he would say that to me! I won't take that from him!"

All reports confirm that Martin finally responded. "What's you argument? I don't have an argument with you. If you have an argument with me, you can meet me in my room."

At which point the argument began in earnest.

Martin refused to confirm what had started the discussion. In response to a question about whether Rivers would be benched indefinitely for lack of hustle, he said, "Whatever happens to Mickey happens."

Munson was unavailble for comment and according to team publicist Mickey Morabito, "has not been talking to anybody about anything all year."

The Yankees, who feuded all the way to the world championship last season, may have one casualty - long time Coach Elston Howard.

"This is it," said one of the peace-makers to the Martin-Munson brouhaha. "This is my last year. I can't take this anymore!"