The term 'Jet Type' is a type of aircraft engine, specifically a turbojet engine. A turbojet engine is a type of internal combustion engine that uses a turbine to compress air and create thrust. The crossword solution for this term is LEAR, which is an acronym for Lightweight Engine for Advanced Research. This engine was developed by the American engineer William Lear in the 1950s and was the first successful turbojet engine. It was used in a variety of military and civilian aircraft, including the F-86 Sabre fighter jet.