Most school bells are ringing as economy discourages teacher strikes

School labor disputes delayed the opening of classes in many communities across the United States in the last days of August, but two major teacher unions expect the relative school labor peace of the last two years to continue into this fall.

Strikes on Aug. 30 held up the start of school for more than 64,000 pupils in at least seven states. The number who will have extended summer vacations could rise above 100,000 this week.

However, the National Education Association (NEA), the largest teacher union, looks for fewer school strikes overall than in 1980 and 1981 because of the poor economy and a sharp increase in teacher unemployment. The American Federation of Teachers (AFT), affiliated with the AFL-CIO, also sees fewer walkouts - not, one official said, because the AFT is ''optimistic about bargaining prospects,'' but because its locals ''recognize the realities of negotiating contracts under today's conditions.''

School contract disputes led to a record 242 strikes in the 1979-80 school year, but walkouts dropped to a reported 191 in 1980-81 and further declined to 111 last year.

But school district negotiators were nervous about a turnaround this fall as union locals demanded large increases to meet sharply higher living costs. AFT has reported early settlement gains of about 18 percent over three years, with 8 to 10 percent gains in a some new contracts this year.

The continuing decline in enrollments has affected schools in most states outside of the Sunbelt and the West. This has led to teacher layoffs in at least 40 states and the District of Columbia. About 16 percent of Massachusetts teachers reportedly have been furloughed to trim school budgets.

Overall, the AFT reports teacher unemployment nationally will rise 21 percent as a result of 55,000 layoffs this fall. The NEA similarly estimates about 50, 000 will lose jobs.

Even with this gloomy outlook, school strikes are looming in about 20 states this fall, double the number that had strikes last year.