The crossword solution for the term 'SHARK's Rival' is JET, a three-letter word. JET is a type of aircraft that is powered by JET engines, which are engines that use a JET of hot exhaust gases to propel the aircraft forward. Jets are typically faster than propeller-driven aircraft and are used for long-distance travel. They are also used in military operations, as they can reach higher altitudes and fly faster than other types of aircraft.