About 80 air traffic controllers at Washington National Airport won a pay increase yesterday when the Civil Service Commission ruled that they should be ranked with the highest-paid controllers in the country.

The commission, acting on a recommendation from the Department of Transportation and its Federal Aviation Administration, ruled that the National controllers do work that entities them to the pay of GS 14s instead of GS 13s. That would mean an average increase of about $5,000 a year, from $28,623 to $33,825, although the precise figure varies with seniority.

National controllers staged a oneday wildcat slowdown last November when controllers at other major airports across the country were awarded the higher rating while National controllers were left at the same scale.

The GS rating of air traffic controllers is based on the number of operations - takeoffs, landings or fights enroute - each control center handles, on averageM in a 24-hour period. National is essentially a 16-hour airport, so the 24-hour rule lowered the average for National, and thus lowered the pay rate for its controllers.

The controllers complained, and air traffic was slowed by 30 to 90 minutes around National. The wildcat slowdown lasted about two days.