The U.S. organized labor movement, confounded for years by declining membership and power, is finding new strength in the recently completed strike by American Airlines flight attendants.

Labor leaders and observers say the strike--by getting management back to the bargaining table on union terms without loss of jobs--has inspired, encouraged and emboldened unions. They predict that strikes--though clearly reshaped--could once again be effective weapons in labor disputes.

Unions have already refilled their quiver of tactics with legal work slowdowns and "corporate campaigns" to sully employers' images with investors and customers. Now organized labor is also learning the value of limited-duration strikes, such as that used by the airline attendants, and "rolling" strikes that move from department to department or building to building. Such strikes are designed to catch management when it is off guard and vulnerable, while also trying to protect workers' jobs.

"They've got to shoot from behind a tree," said Stanley Aronowitz, a sociology professor and labor specialist at City University of New York, who predicts labor unions will become more militant and more likely to use guerrilla tactics.

Aronowitz said the apparent success of the flight attendants, the quick intervention by President Clinton and the historically strong ties between unions and the Democratic Party mean that perhaps "the period in which management had a distinctively upper hand has come to an end."

For their part, business representatives foresee greater use of limited-duration strikes, but they are reluctant to concede any loss in power or a change in direction for labor-management dispute resolution.

Many in the business community agree with Daniel J. B. Mitchell, professor at the Anderson Graduate School of Management at UCLA, who said the political climate--much changed since the round of devastating airline strikes in the 1980s--had more to do with the quick resolution of the strike than any strategy used by the flight attendants.

Still, executives are likely to soften "supermacho" posturing at the bargaining table, said Audrey Freedman, a New York economist and management consultant. The hard-line stance by American Airlines was unsuccessful; a similar stance by Eastern Airlines led to the carrier's failure, she said.