Question: what are the 5 generations of fighter planes?
Answer: First generation subsonic jet fighters (mid 1940s to mid 1950s) ...  Second generation jet fighters (mid-1950s to early 1960s) ...  Third generation jet fighters (early 1960s to 1970) ...  Fourth generation jet fighters (1970 to late 1980s) ...  Four and half generation jet fighters (late 1980s and into the 90s)