The tense battle between smokers and nonsmokers reached new heights yesterday when the pilot of an Eastern Airlines shuttle from Washington to New York set the flight down abruptly in Baltimore because of squabbling in the aisles.

"People were getting out of their seats . . . and actually grabbing at the flight attendants back there," said Capt. Larry Kinsey, pilot of the 177-seat Boeing 727 jet. They "were interfering with the flight crew members in the performance of their duties."

"I haven't seen a display like this since kindergarten," Washington passenger Emory Kristof told the Associated Press when the plane finally reached New York. "We had to land the plane and sort out everybody's dollies and metal toys."

Just exactly what happened aboard the 8 a.m. flight from Washington National Airport to New York's LaGuardia Terminal remained somewhat in question last night.

Each of the several versions of the story, however, involved Richard Lent, a Washington lawyer with the firm of Caplin & Drysdale.

Everyone seems to agree that Lent boarded the 8 a.m. flight, looked for a seat in the non-smoking section and, finding none, asked the flight attendant to give him a nonsmoking seat.

The captain, all agree, then asked for volunteers in the nonsmoking section to yield a seat to Lent.When there were none, the nonsmoking section was expanded to include Lent.

Once the no-smoking light went off, Lent said, "several people lit up," including one in the expanded nonsmoking section. "Shortly after that, a stewardess came around and talked to the two people that I saw light up. I guess she asked them not to smoke. I didn't instigate that."

Harry Fisdell, executive vice president of the New York Newspaper Guild and a passenger on the flight, told the Associated Press that the dispute began when Lent demanded that everyone near him stop smoking.

Then, Fisdell said, Capt. Kinsey announced, "I'm telling you people, this insurrection has to stop or I'm going to land the plane." Lent said he heard no warning.

Two minutes later, Fisdell said, the pilot announced, "Well, the insurrection hasn't stopped. I'm landing." And he did, in Baltimore.

A passenger sitting about 10 rows in front of Lent said he did not hear a problem behind him, only the pilot's announcements.

"I don't think a lot of people knew what was going on in the back of the plane," Capt. Kinsey said. "The chief flight attendant was notifying me continually."

Two officials from the Federal Aviation Administration office at Baltimore-Washington International conducted brief interviews with Lent and others.

Another plane was brought in, and 151 of the passengers were taken to New York. The rest returned to Washington, their cab fare paid by Eastern.

One passenger who returned to Washington said, "I had to get on the phone and cancel appointments. I was busted for the day. Somebody should have been arrested."

The Civil Aeronautics Board's rules require that nonsmoking seats be available for all who ask for them. "We'll investigate if someone writes a letter and complains," a CAB official said. The FAA is investigating to see if there was interference with the flight crew, which can be either a civil or a criminal offense.

Tom Myers of Eastern Airlines said, "We're not ruling out the possibility of legal action. We're trying to find out precisely what did happen before we make a final decision."

Lent said he received both praise and condemnation from his fellow passengers, many of whom were late for appointments in New York or who had to cancel appointments.

As for Lent, he said, "I wanted a non-smoking seat. I knew I was entitled to it. I didn't demand anything. I just told them I was going to write to the CAB."