On wings and on wheels, through clear skies and beneath them, thousands of Washington residents streamed back to town yesterday as the Thanksgiving holiday weekend came to an end with another traditional observance -- one that might aptly be named National Travel Day.

For those making their pilgrimages by automobile, whether they were returning here, or leaving for schools, jobs and homes elsewhere, "it looked like rush hour all day long," said a Washington area spokesman for the American Automobile Association.

At the Baltimore Harbor Tunnel, traffic was backed up for five miles in each direction for a time, a spokeswoman said. At National Airport, according to an operations officer, it was a "very busy day," and Amtrak trains had hundreds of riders standing in the aisles.

While the heavens smiled on voyagers throughout the Northeast and the sun shone brightly out of what might have been called a travelers' sky, an unexpected snarl on the rails caused delays for passengers riding the packed Amtrak trains through the bustling Boston-New York-Washington corridor.

A Philadelphia-to-Boston train was stopped in New Haven for about an hour and a half while police made a futile search for four men believed to be carrying guns.

Overall, the average delay was about 10 to 20 minutes, according to Amtrak spokesman John McLeod, but passengers on one Boston-to-Washington train told of arriving here two hours late.

Amtrak officials said that, to accommodate holiday travelers on a day that has become legendary for its demands on transportation facilities, they added 61 trains to the more than 100 that normally serve the Northeast corridor on weekend days. Each of the extra trains generally included from eight to 10 cars, McLeod said.

Since Wednesday, McLeod said, 5,725 people were forced to stand for at least part of their Northeast corridor trips. On a normal weekday, he said, everyone riding on trains in the corridor can find a seat for the entire journey. "This is our peak period," he said.

"We keep adding on as many buses as we need," said a spokesman at the downtown Greyhound terminal, and apparently many buses were needed. Traffic was heavy, the spokesman said, adding that this is "normal for the Sunday after Thanksgiving."

Metrorail service, which normally ends at 6 p.m. on Sundays, was extended until midnight for travelers' convenience. A spokesman described ridership as moderate.

Highway traffic congestion "was much worse this year," at least in part because of the good weather that appeared to encourage motorists, said AAA spokesman Tom Crosby. He said traffic seemed particularly heavy on Rte. 1 and on the George Washington Parkway, both of which provide access to National Airport.

At the airport, an Eastern Airlines official said that extra planes and crews enabled the airline to make 30 shuttle flights to and from New York, or twice as many as normal.

While Eastern carried what George Burgess, passenger services manager for the airline at National, described as a "good volume " of travelers, he said that the numbers were down from a few years ago.

Deregulation, he explained, had put more airlines into the market and more seats into the air, reducing the passenger loads carried by individual lines. Bumper-to-bumper traffic on the roads in and around the airport, however, indicated that the total number of travelers was in keeping with seasonal tradition.

It was not only travelers fearful of missing their flights who showed the day's strain. The crush placed a heavy burden on those assigned to prevent the arrival of anarchy and permit the departure of passengers.

A motorist in the short-term unloading lane at the airport terminal appeared bent on making a long-term stop. An officer flashed his book of tickets, and the driver flew into a rage.

"I get one of those [people] every three minutes," said the officer, adding that his assignment made it necessary for him to take a five-minute walk from time to time "to calm my nerves." Inside the terminal, there also were signs at times that the next stop could be chaos.

"It's wild," said skycap Earl Dudley, speaking both of yesterday in particular and the Sunday after Thanksgiving in general.