kozmund sez: Abbreviated as ASBM, this is an air launched ballistic missile whose range exceeds 600 kilometers. Unlike ALCMs , they do not sustain their flight through aerodynamic lift. Rather, their trajectory is entirely ballistic.

/me sez:
The United States developed (although, to the best of my knowledge, never deployed) a rather unusual ASBM in the 1960s. In a triumph of overengineering, a Minuteman II ICBM (perhaps minus one stage, I'm not sure) was loaded onto a cargo plane and dropped horizontally out the rear doors. A parachute deployed, which steadied the missile into a tail-down fall. As soon as the swing rate dropped below an acceptable level, the main engines fired, lifting the missile into normal ballistic flight. I expect that it enjoyed a slight range boost, since it was starting its flight a few miles above ground.

The problems with this approach were legion; despite its relatively safe solid-fuel rocket motors, a fully-armed nuclear ICBM is not something you really want to be flying around with, especially when it's of a size that forces it to 'hang out' of the rear of the airplane during takeoff and flight. Also, much of the 'aiming' of an ICBM depends on extremely accurate knowledge of its starting point. Although modern versions might use GPS to get a fix while in free-fall downward, no such option was available in the 1960s.

Actually, I have learned that there is a system in use by the United States which utilizes the top stage of a Minuteman and a C-130 to provide targets for missile defense tests. This (the original) really worked, though (as in, launched and didn't blow up or bring down the plane). There's a film clip of the launch that pops up on the Discovery Channel or A&E once in a while. It's pretty damn impressive.