Wednesday is "airport day" at the U.S. Magistrate's Court in Alexandria. An assistant U.S. attorney calls it a zoo.An airport policeman jokingly says it is "always good for a few laughs" and he hates to miss the weekly show.

It is the one day of the week when police from Washington National and Dulles International airports testify in their traffic, trespassing and parking violation cases at the magistrate's court. Through the good humor of the magistrates and the offhand comments of spectators, some violators even leave the courtroom smiling, albeit a bit poorer.

During a typical Wednesday, Magistrate Harris Grimsley, in his high-pitched voice, will call out about 150 names of people summoned to court for allegedly committing a variety of petty offenses on federal property.

At a recent court session, after reading a dozen names of people who did not show up, Grimsley hesitated at one.

"Mary Hartman," he called, breaking into a laugh.The spectators guffawed and slapped their knees.

But the real entertainment begins when people start trying to explain why they should not be fined.

One young man, Steven G. Williams, told Grimsley the reason his car was left unattended at National Airport was that his girl friend, rushing to catch a flight, accidentally took his keys. Williams then had to catch a cab, go home and return with spare keys. By that time he had been ticketed, Williams said.

Grimsley fined him $25 anyway.

Many cases involve foreign-born cab drivers at the airports who don't seem to understand ticketing procedures of the American police officer, said Assistant U.S. Attorney Elsie Munsell.

"The cultural confrontation between the foreign-born taxi driver and the American-born policeman is sometimes incredible to watch," Munsell said. "Their (taxi driver) response to a ticket is to jump out of a cab and throw themselves on the ground and call on all their relatives about this injustice."

She said some of the drivers have prostrated themselves in front of the magistrates as well.

One cab driver who seemed to speak every other word in an Oriental language told Grimsley Wednesday why he refused to obey a police officer at National who told him to keep driving and not stop traffic.

"I had enough," the cab driver said. "I pay 56 cents a gallon (for gasoline). I go 'round (the airport traffic circle) one mile, twice. Twice."

Grimsley rested his head in his hand as courtroom spectators leaned forward to hear what the small cab driver, who was waving his arm and prancing around in front of Grimsley's bench, was saying.

"You've done a nice job here presenting your case," Grimsley said. "But I think you're just as guilty as can be."

The man tried to explain again and Grimsley finally said, "I tell you what. Let's both quit." Grimsley dismissed the charge.

The spectators laughed again.

But there are some grim moments, too.

In one case, two young women and four men were charged with trespassing on a Dulles landing field and tampering with runway lights.

"That's a poor spot to commit a prank," Grimsley told the youths. "You've read newspapers about all the (airplane) accidents lately. But we were all young once and we get into a little difficulty once in a while."

The youths negotiated with an assistant U.S. attorney and eventually pleaded guilty to a lesser type of trespassing. The four men paid $75 for trespassing and tampering and the women, who pleaded guilty only to the first offense, were fined $25.

For the most part, the courtroom atmosphere is friendly and informal and the accused seem to delight in cross-examining a police officer who has testified against them.

A woman from Seat Pleasant raised her voice and began pointing her finger at Officer Robert J. Emmerton who had ticketed her for parking in a loading zone at Dulles. When Grimsley asked the woman if she wanted to question Emmerton, the woman was silent, then several seconds later began shouting at the policeman and starting crying. She said she had rushed to Dulles so her daughter could catch her flight.

"My daughter had eight pieces of luggage and two children," the woman said as she sniffled into a tissue. "I had to rush in the airport and I didn't even get a chance to say goodbye to my kids."

Grimsley said he would give the woman the benefit of the doubt and dismissed the case.