The Senate last night rejected a House-Senate conference report that would have required costly airline payments to pilots and other employes whose jobs are affected by mergers, route transfers or the sale of as little as 20 percent of an airline's planes or other assets.

By a 59-38 vote, the Senate agreed with Sen. Nancy Landon Kassebaum (R-Kan.), chairman of the aviation subcommittee, that the conference had violated Senate rules by going beyond House and Senate measures in adding "new matter" by adding the controversial labor-protection provisions.

The provision had been attached to a noncontroversial airline industry bill.

The protection provisions would have guaranteed laid-off employes up to 60 percent of their salaries for up to five years.

The measure also would have provided compensation for wage losses to employes transferred to lower-paying jobs, moving allowances, merged seniority lists and binding arbitration.

The defeat of the conference report was a blow to the Air Line Pilots Association and the International Association of Machinists and Aerospace Workers, who lobbied hard for the bill; for the adminstration, which first opposed the bill, then became neutral, then worked for its passage; and for Senate Commerce Committee Chairman Bob Packwood (R-Ore.) and Ranking Minority Member Howard Cannon (D-Nev.), who supported inclusion of the provisions during the conference.

The airlines vigorously opposed the provisions on grounds that they would inhibit necessary steps to restructure operations in a difficult operating environment.

Kassebaum called the measure "a major step backward from deregulation" that would have imposed new government-mandated conditions on airline transactions. She drew support from senators who opposed the labor protection provisions in principle and also those who felt Senate rules had been violated.