A settlement was reached in a $50-million lawsuit filed against a commuter airline by the mother of Samantha Smith, the Maine schoolgirl and peace envoy killed in a 1985 plane crash. Terms of the settlement between Jane Smith and Bar Harbor Airlines were not revealed on agreement of both parties, said Bar Harbor spokesman Steve Mason. Samantha, 13, of Hallowell, Me., her father, Arthur, and six other people were killed Aug. 25, 1985, when Bar Harbor Flight 1808 from Boston crashed near an airport in Auburn, Me. They were returning home from London, where Samantha had filmed a segment of the TV series "Lime Street." Samantha gained fame in 1982 when she wrote then-Soviet leader Yuri V. Andropov of her concerns about the dangers of nuclear war, and Andropov invited her to tour the Soviet Union.