Douglas A. Fraser, leader of 1.2 million auto workers, stood at the foot of a long, descending escalator at the Atlanta airport, looking up.

"Think we oughta try it?" he asked Joe Loesche, who has been driver-bodyguard-companion for every United Auto Workers president since the late Walter P. Reuther. The two have a running joke about their occasional sprint up a Down escalator, about the funny looks they get, these two crazy silver-haired guys.

To travel around with Fraser for a few days just before Labor Day, it was hard to believe he is 65 and will soon give up his powerful position to retire to some quiet teaching job. And it was easy to forget that he is presiding over the darkest period in the history of his union.

Fraser acts like a guy who enjoys running up life's Down escalators. To many Americans, he is only vaguely familiar from television news as the down-to-earth labor leader who won a seat on the Chrysler board of directors and convinced his membership to make concessions estimated at $4.5 billion to help a mortally stricken auto industry recover.

Fraser's union has lost over 300,000 members in the past five years and many will never return to the assembly lines. Foreign auto makers have captured 31 percent of the market in the United States for what was once the quintessential American product.

Fraser's retirement, scheduled for next summer, is viewed by many in the labor movement as "the end of an era." He is the last UAW chief to be drawn from the inner circle of Reuther, the Depression leader who forged the union into a potent social and political force.

Fraser, who has been UAW president since 1977, is respected as a gutsy leader with a gruff, crusty humanity. A high-school dropout who married a university professor, he lives with his wife in a small co-op apartment near downtown Detroit, travels coach with his long legs scrunched up on his briefcase, refuses the fancier cars that come with his job and says nasty things about labor corruption. Open, approachable and good-humored, but with a hair-trigger temper betrayed by a sudden reddening of the face, he draws crowds wherever he goes.

In this recent round of speeches, news conferences, trips to Washington for an AFL-CIO meeting, to Knoxville and Tulsa for union gatherings, and work in his Detroit headquarters, Fraser started to acknowledge the strain of what promises to be a painful leave-taking from the world he entered as a teen-age fender-mender about a half century ago: months and months of sentimental hugs and handshakes and questions.

Some people may worry about pressure, but "I think Doug is worried about how he's going to get along without stress and pressure," said his trim, outgoing wife Winnifred -- "Winnie" to friends -- a dean at Wayne State University.

That week, Fraser had much to worry about. The Chrysler negotiations were heating up again. The Canadian UAW was threatening to strike rather than make concessions as its U.S. brothers had -- the first major split in the union's international membership. General Dynamics, formerly the Chrysler tank division, was on the verge of a potentially violent strike. All were expected to come to a head by mid-September.

Fraser also was getting angrier and angrier about congressional resistance to the union's number one legislative priority: a controversial bill to protect auto industry jobs by requiring foreign auto makers that sell cars in the United States to make the bulk of them here. Fraser blamed the delays on House Commerce Committee Chairman John D. Dingell, the Democrat from Detroit. By the end of the week, he vowed softly, "I don't think I'll ever speak to John Dingell again. He let us down."

Fraser said he gets weariest with all the questions about lazy, greedy workers and why aren't they to blame for the soaring prices and declining quality of cars, inflation-inducing high wages and so on. "It takes two to tango," he said at one point, insisting that managers share the blame with workers and that in any case the situation was not so easy to size up way back in 1979, before the roof fell in.

One night, he reminded a Detroit audience of auto industry managers and suppliers that just two or three short years ago even the Japanese small cars were hard to sell. "And you couldn't give away Vegas or Pintos -- first of all they were rotten cars big laugh -- but the people of the United States really wanted to drive large cars . . . . We had an absolute monopoly, in large cars . . . . So I think there was a tendency to be self-satisfied, complacent. All of this contributed to our downfall."

Another evening, Fraser had a rare, small "victory" to celebrate by sharing a pitcher of light beer with his staff at a neighborhood bar next to the bleak hulk of a shut-down rubber factory, near UAW's Solidarity House. A Reagan administration official, Michael Driggs of the Department of Commerce, had come to Detroit and enraged the community by saying unemployed auto workers weren't as bad off as everybody thought, thanks to their benefits and working wives and so on, and that in fact they had an average income of $28,000.

Fraser and his young public relations chief, David Mitchell, had thrown together an impromptu news conference at which Fraser, flanked by a couple of black unemployed workers whose benefits had run out, called Driggs a cynical, cruel "bum." The story got a lot of play across the country, at the same time the administration was trying to convince the public it is not insensitive.

Later, with his lopsided grin, Fraser said, "I know Mac Baldrige Driggs' boss, Secretary of Commerce Malcolm Baldrige . I think I'll give him a call and see if he'll let Driggs out of his cage one more time, see if we can't get him back here again before the election, maybe get him to go to Ohio, and Pennsylvania and some other states, too . . . ."

The "succession thing," Fraser said, as he waited in one of those plastic airport chairs one day, "is starting to bother me."

One of the fears that has caused him some sleepless nights is that, under his successor, the union might abandon its tradition as a progressive social force, he said. There is a belief in some quarters that this was a role UAW leaders could afford to play only as long as times were fat and the rank-and-file was in clover.

Although the membership, as wages improved, has grown more and more conservative and middle class, all of the contenders for Fraser's job express a commitment to what they call the "Reuther legacy:" compassion for the poor, support for the causes of women and blacks. But, said Fraser, "it's like anything else. There are shadings, and some are more committed than others."

Fraser, who was born in Scotland, the son of an electrician, has always been an activist, a left-wing Democrat, who counts among his credits the desegregation of a union hall toilet in Memphis as far back as the late 1940s.

It's true, he told a group of black journalists, that many union members resented certain costly social programs. But President Reagan has given them a new perspective. Many are no longer protesting because now "they're on food stamps themselves."

Fraser has refused to say whom he favors as a successor. The decision will be made by the UAW's 26-member executive board. The two front runners reportedly are UAW Secretary-Treasurer Raymond Majerus and Vice President Donald Ephlin, with two other vice presidents trailing.

Fraser and his predecessor, Leonard Woodcock, each had 15 years in national union offices to establish themselves, he said. "These poor guys, all of them have only been there for 2 1/2 years, the worst goddamned years in the history of our union, so it's really unfair . . . ."

On a visit to Knoxville, Tenn., Fraser was greeted with the sort of spine-tingling union theater sure to shake up even the most hardened right-to-worker. It was a political "summer school" for union members from all up and down the eastern seaboard and across the South, designed to get out the union vote this fall.

As the regional leader proudly led him into the auditorium, 500 men and women in "Buy American" caps sprang to their feet, raised their clasped hands high over their heads and started to sing along with two union guitarists on the stage. They sang the union anthem, "Solidarity Forever," to the tune of "The Battle Hymn of the Republic:"

"It is we who plowed the prairies, built the cities where they trade . . . Now we stand outcast and starving 'midst the wonders we have made . . . But our union makes us strong!"

Fraser talked to them bluntly about the hard facts of life in the auto industry, but assured them he would grant no further concessions to Chrysler (they cheered).

And he told them goodbye. "This is the last time I will address you as president," he said, and went on to pave the way for the next fellow. The struggles of the '30s and '40s were difficult "physically," he said, but "not nearly as difficult and complex as those of today."

He said he has heard the talk that, because the new crop of leaders was not reared in the Depression, they lack the sense of commitment of Fraser's generation. "I don't accept that. Commitment is an intellectual development."

What his successor can look forward to coping with, besides "enormous pressures," Fraser said later, are a smaller but more highly skilled and secure membership, more trimming in the staff of the UAW itself (Fraser has cut 95 people), a fast-changing industry, a continuing need for "flexibility" at the bargaining table. Also, there is the fact that layoffs have gutted a whole younger generation of workers.

He believes the old adversarial spirit will resurface in labor-management relations to some extent when the economic pie expands again. "But what will never, never change again is the so-called democratization of the work place."

Though many unionists miss the good old days, Fraser said, he prefers the new, better-educated workers who question the union leader, as well as the boss. "When I was a steward, Christ, the people would just do anything I wanted and they didn't even ask me why."

He said this despite the fact he suffered one of his greatest disappointments in the recent General Motors negotiations, when he was unable to sell his membership on an initial agreement and, on a second try, won approval with only 52 percent of the vote.

On Labor Day, Fraser said, he planned to march in a parade in Detroit. "Me and probably about five other guys," he added with a sharp, dry laugh. The workers have other things to do these days, thanks to their union. "They go to their weekend cottages. Their cottages! Me, I still love a Labor Day parade."