Jet Missing With Two Men AboardPresque Isle, Dec. 16—»(/P)—An F-89 jet fighter plane and its two-man crew vanished from, chilly northern Maine skies yesterday, and Air Force, state and.’ local agencies mounted a search;Neither of the men—a. pilot and radar observer—was Identified by the Presque Isle Air. Force Base. A base spokesmaii said the jet, aloft on a local trainingflight, ran low on fuel apparently in the Presque Isle vicinity. ,