The Phoenix could be launched from a 100 miles away. Its flight trajectory would be about the same through most of the flight as with the standard model. The missile would accelerate and climb in altitude to reach mach 5. Upon reaching the target location, it would go into a steep dive to hit the target on the ground. The AIM-54 was also designed to target low flying cruise missiles in much the same way.

IMO, such a missile is far too valuable a weapon to let slip into history. The design is over 30 years old and the technology is very well understood. Its range and speed are unmatched by any currently fielded missile and I believe that it's an excellent platform to expand upon. If Osama (or some other high priority target) were ever located at a certain location, such a weapon could be launched from a long way off and hit him very quickly.

I never understood why it wasn't deployed on F-15s.