The F-16 has been procured to serve in the air forces of 25 other nations and as of 2015, it is the second most common currently operational military aircraft in the world. The most common military aircraft is the Sikorsky Blackhawk.
The Fighting Falcon has key features including a frameless bubble canopy for better visibility, side-mounted control stick to ease control while maneuvering, a seat reclined 30 degrees to reduce the effect of g-forces on the pilot, and the first use of a relaxed static stability/fly-by-wire flight control system which helps to make it a nimble aircraft. The F-16 has an internal M61 Vulcan cannon and 11 locations for mounting weapons and other mission equipment. The F-16's official name is "Fighting Falcon", but "Viper" is commonly used by its pilots and crews, due to a perceived resemblance to a viper snake as well as the Battlestar Galactica Colonial Viper starfighter.