The nation's airlines went to court yesterday in an effort to head off the possibility of slowdowns by some air traffic controllers over the holiday weekend. Few if any delays yesterday were linked to the controllers.

Except for "isolated cases," the "considerable" delays in air traffic experienced yesterday were due to bad weather, the large number of flights, or other circumstances unrelated to any actions of controllers, said Federal Aviation Administration spokesman Dennis Feldman.

Earlier this week, the head of the controllers' union warned three airlines that they might trigger nationwide slowdowns unless they allow controllers to make free, unconditional overseas "familiarization" flights.

John Leyden, head of the Professional Air Traffic Controllers Organization said he would not call a slowdown, which would be illegal, nor could he predict when and if one might come. But given the mood of the controllers, he said a job action was likely unless the unconditional free international flights were approved. The flights are part of a contract between PATCO and the FAA. 0599 - Add two controllers TTS Burke.

A spokesman for the Air Transport Association said the group obtained an order in federal court in Brooklyn yesterday directing the controllers to show cause why they should not be held in contempt for possible violation of an injunction issued earlier that bans any slowdowns.

PATCO spokesmen could not be reached immediately for comment last night.

Feldman, the FAA spokesman, said delays Thursday night at Kennedy International Airport in New York clearly stemmed from a job action. Other than that, he said, no other delays had definitely been attributed to controllers.