Unionized workers who went along with contract concessions and moderate settlements during the recession now are beginning to flex their muscles at bargaining tables. The outcome is expected to be somewhat larger contract settlements and more strikes in the year ahead.
The first confirmation of this is expected in aerospace bargaining between the United Auto Workers and McDonnell Douglas Corporation. Negotiations opened in California Aug. 22 with UAW Secretary-Treasurer Raymond Majerus, director of the union's aerospace department, predicting ''substantial wage gains and other economic improvements.''
The talks open a new cycle of negotiations in the aerospace industry, in which UAW and the International Association of Machinists represent 55,000 workers. Settlements are expected to set goals for other industrial unions bargaining later this year and in 1984.
Meanwhile, signs of labor's tougher bargaining stance are showing up in other situations:
* Telephone workers represented by the Communications Workers of America (CWA) and two other unions struck the American Telephone and Telegraph Company nationally to win a larger wage increase than AT&T offered, more job security, and no substantial ''give backs'' to management.
Telephone unionists still must approve an estimated $3 billion settlement that includes wage increases of 8.5 to 9 percent (an average $30 a week) over three years, cost-of-living raises, and what CWA calls ''ground-breaking gains in job security'' and ''a victory'' over AT&T demands for concessions. Ratification of the agreement is expected, but surprisingly hard bargaining over local issues had delayed a return to work.
* General Motors workers at Packard Electric Division operations in Warren, Ohio, turned down a ''revolutionary wage deal'' worked out by management and a local of the International Union of Electrical Workers. The 5,301 to 2,084 vote stunned both management and leaders of the local union, who had predicted approval of the plan.
The deal would have drastically cut wages of newly hired workers in an effort to preserve jobs. Management had threatened to stop hiring new employees in Warren because of the high labor costs. Unionists who turned down the plan say they feared GM intended to undercut the entire wage structure at the plant.
GM won concessions from Packard workers worth more than $600 million during the past two years.
* The International Association of Machinists appears to be losing a strike against Continental Airlines, called to save several hundred jobs and to avoid a wage freeze. Continental has worked out cost-savings deals with pilots and other unions and expects to be flying normal schedules by Sept. 1, though the machinists are holding firm so far.
* Other strikes are under way by machinists against the American Hoist and Derrick Company, since June 1; the United Rubber Workers against a Canadian General Tire and Rubber Company plant, since July 3; the United Steelworkers against the Phelps Dodge Corporation, since July 1; by 10 unions against West Coast shipbuilders; and by unions in a number of other industries. In most, managements are seeking wage or other concessions, and unions are resisting them.
Until recently, time lost in strikes this year was running at the low level of .04 percent of all working time, far below the .1 percent level in the late 1970s. Most contracts still are being negotiated peacefully, but the number of strikes is rising.
In part, this is a result of more aggressive negotiating tactics by managements seeking lower labor costs and the elimination of thousands of union jobs they consider expendable. In part it is a decision by unions that, with the economy turning up again, ''we'd better stand and fight now before it's too late ,'' in the words of Arthur Osborn, president of the Massachusetts AFL-CIO.
Underlying that position is a growing recognition in union leadership that labor's rank and file are increasingly bitter about their leaders' ''softness'' in concessionary settlements. A union activist spearheading the revolt against the Packard agreement said, ''We've given up enough. No more.''