The term 'kind of aircraft' can be answered with three different solutions: ENEMY (5 letters), JET (3 letters), and FANJET (6 letters). An ENEMY aircraft is any type of aircraft used by an opposing force in a conflict. A JET is an aircraft propelled by one or more JET engines, which are engines that generate thrust by ejecting a high-velocity stream of air and fuel. A fanjet is a type of JET engine that uses a fan to increase the pressure and velocity of the air entering the engine.