The McDonnell Douglas AV-8B Harrier II began development in the late 1970s as a major evolution of first generation Harrier. The AV-8B entered service in 1985 and featured improved range, payload, and avionics - enhancements that proved invaluable during conflicts such as the Gulf War, operations in the Balkans, Iraq, and Afghanistan. Continuously upgraded with night-attack and radar-equipped variants, the Harrier II remained a cornerstone of Marine expeditionary aviation into the 21st century until it began transitioning to the F-35B Lightning II.