The Boeing AGM-86 is a sub-sonic air-launched cruise missiles (ALCMs). The ALCM is being replaced in the nuclear role by the AGM-129 ACM, with most ALCM's being converted to carry conventional warheads.
The small, winged AGM-86 missile is powered by a Williams F107 turbofan jet engine that propels it at sustained subsonic speeds and can be launched from both high and low altitudes. After launch, the missile's folded wings, tail surfaces and engine inlet deploy. The nuclear AGM-86B is then able to fly complicated routes to a target through use of a terrain contour-matching guidance system (TERCOM). The conventionally armed AGM-86C uses an onboard Global Positioning System (GPS) coupled with its inertial navigation system (INS) to fly. This allows the missile to guide itself to the target with pinpoint accuracy.
An enemy force would have to counterattack each of the missiles, making defense against them costly and complicated. The enemy's defenses are further hampered by the missiles' small size and low-altitude flight capability, which makes them difficult to detect on radar.