AFL-CIO President Lane Kirkland yesterday urged the Reagan administration to rehire fired air traffic controllers, since their union has been ordered to disband.

"Any continued vendetta against these workers and their families would not be justice, but revenge," Kirkland said.

He said the 2-to-1 decertfication order Thursday by the Federal Labor Relations Authority "confirms the ability of the government to use its enormous power to break this small union."

The ruling, now contested in the U.S. Court of Appeals here, was made against the Professional Air Traffic Controllers Organization for calling an illegal strike that began Aug. 3. An estimated 11,438 of the 13,000 PATCO members who participated in the strike have been fired.

Kirkland said the AFL-CIO "deplores the majority decision" of the FLRA. He said the ruling "does not, and indeed could not, answer the real questions at stake--how to promptly restore the air traffic system to full and efficient operation, and how to do so while providing controllers fair working contitions."

Kirkland, other labor leaders and some members of Congress have expressed doubts that the government can rebuild the nation's air traffic control system in a timely manner--by 1983--without rehiring the fired controllers.

But the Reagan administration, with Transportation Secretary Drew Lewis as its point man, has refused adamantly to rehire the fired controllers. Lewis repeated yesterday on "Good Morning America" (ABC, WJLA) that the administration will not change its position.

Some Transportation Department officials said the administration's position was reinforced through governnment interviews with working controllers who say that rehiring strikers would create tension and lower already dipping morale in airport towers and air traffic centers.

About 5,700 controllers, including 2,000 PATCO members, did not strike. If the appeals court upholds the decertification ruling, working nonsupervisory controllers could be organized by another union.

Labor sources say the Teamsters, who have an airline division based in Chicago, sent organizing feelers to controllers at O'Hare International Airport in Chicago and in the New York metropolitan area