“Fifth-generation” and “sixth-generation” have become buzzwords for modern fighter jets. The concept of there being different generations of fighter jets appeared in the 1990s, and it should be stressed that there is no hard and fast definition of what it takes for a combat jet to belong to a particular generation of fighter jets (which is partly why there is debate about whether a given aircraft really is a fifth-gen fighter). Fighter jets are placed into generations in an attempt to classify the major technological leaps in the development of the jet fighter.