Washington area airports reported that commercial traffic picked up slightly yesterday on the second day of the air traffic controllers' strike.

National Airport accommodated 447 of its normal 620 commercial air carrier flights on Monday; yesterday "slightly more" planes were taking off and landing, according to tower chief Harry Hubbard.

Hubbard said the number of controllers staying away from jobs at National remained about the same, although he declined to give a precise number. On Monday, only two of 19 controllers scheduled for the morning shift showed up.

Yesterday, Baltmore-Washington International operated about 101 of 125 scheduled commercial flights, according to Operations Manager Charles Sander. He called this an improvement over Monday's levels.

A spokesman at Dulles International reported a slight increase in traffic compared with Monday. None of the striking controllers there returned to work yesterday, he said. All controllers scheduled for the morning shift failed to appear.

At the regional air traffic center at Leesburg, deputy chief Ed Bland reported that three striking controllers had returned to work. On Monday the center handled about 69 percent of the traffic experienced on the pervious Monday, and Bland felt that levels yesterday were somewhat higher, possibly by as much as 10 percent.