A small plane attempting to land at the Frederick Municipal Airport crashed Friday night, killing the pilot shortly after a plane carrying President Reagan made an unscheduled landing at the small airport because of heavy fog.

Civil Air Patrol Maj. Robert Ayres said planes attempting to land at Frederick were put on holding patterns to make way for Gulf Stream III just after 5 p.m. EDT Friday. In Washington, a White House spokesman said the presidential plane was forced to land by instruments alone, necessitating that only one aircraft land at a time.Reagan's plane landed at 5:32 p.m., coming to a full stop at 5:35, according to the White House military command. Reagan then proceeded to the Camp David, Md., presidential retreat in a motorcade, the spokesman said.

The Piper Cherokee Arrow plane was cleared for landing about 45 minutes later but "didn't reappear for radar," Ayres said. The plane was found in a heavily wooded park 5 miles east of the airport.