The term 'SOME JETS' refers to three different types of aircraft. LEARS (5 letters) are Light Executive and Regional Aircraft, which are typically used for short-haul flights. JUMBOS (6 letters) are large commercial jets, such as the Boeing 747, which are used for long-haul flights. SSTS (4 letters) are Supersonic Transport Aircraft, which are capable of flying at speeds greater than the speed of sound.