Basic fighter maneuvers (BFM) are tactical movements performed by fighter aircraft during air combat maneuvering (ACM, also called dogfighting), to gain a positional advantage over the opponent. BFM combines the fundamentals of aerodynamic flight and the geometry of pursuit, with the physics of managing the aircraft's energy-to-mass ratio, called its specific energy. Maneuvers are used to gain a better angular position in relation to the opponent. They can be offensive, to help an attacker gain an advantage on an enemy; or defensive, to help the defender evade an attacker's weapons. They can also be neutral, where both opponents strive for an offensive position or disengagement maneuvers, to help an escape. Classic maneuvers include the lag pursuit or yo-yo, which add distance when the attacker may overshoot the target due to higher airspeed, the low yo-yo, which does the opposite when the attacker is flying too slow, the scissors, which attempts to drive the attacker in front of the defender, and the defensive spiral, which allows a defender to disengage from an attacker. Situational awareness is often taught as the best tactical defense, removing the possibility of an attacker getting or remaining behind the pilot; even with speed, a fighter is open to attack from the rear. Introduction Basic fighter maneuvers (BFM) are actions that a fighter aircraft makes during air combat maneuvering, historically known as dogfighting. The development of BFM began with the first fighter aircraft, during World War I, then continued with each following war, adapting to the changing weapons and technologies. Basic fighter maneuvers consist of many varying tactical turns, rolls, and other actions to get behind or above an enemy, before the opponent can do the same. BFM are typically universal maneuvers which can be performed in almost any fighter aircraft, and are usually considered to be training maneuvers. Training usually begins with pilots flying the same type of aircraft, pitting only their skills against each other. In advanced training, pilots learn to fly against opponents in different types of aircraft, so pilots must learn to cope with different technological advantages as well, which more resembles real combat. In actual air combat maneuvering, variations of these basic maneuvers may become necessary, depending on the different types of aircraft involved, the weapon systems each side is using, and the number of aircraft involved. BFM are used in the three-dimensional arena of air combat, where maneuvers are not limited