Air travelers will soon find that they cannot avoid parking fees at National Airport by leaving their vehicles at five Virginia Metrorail stations, Metro board Chairman Joseph Alexander said yesterday.

Alexander, a Fairfax County supervisor, said he had asked Metro to prohibit parking for more than 24 hours at the Huntington, Vienna, Dunn Loring and West Falls Church stations in Fairfax County and at the East Falls Church Station in Arlington. Automobiles left more than 24 hours will draw $25 tickets and will be towed after 36 hours, he said. Alexander said he hoped that the policy will take effect by Oct. 17.

Parking has not been limited at the stations, but Metro police do tow vehicles deemed abandoned, a spokeswoman said. At the five Virginia stations with large outdoor parking lots, drivers pay $1.50 to drop off a car at rush hour or park free or for a lesser charge the rest of the day.

At National, parking costs up to $7.50 for 24 hours in the daily lots. Parking in the satellite lots costs up to $6 a day. Short-term parking is $2 an hour up to $20 for 24 hours.

Alexander said officials cannot prove that airport travelers are using Metro lots, but he noted that "Huntington is only 10 minutes away {from National} and it doesn't cost a cent to park there." Metro police have found up to 30 cars at a time parked for more than 24 hours in the Huntington lot, he said.