The 747 technology was obsolete and scrapped. There are tenders out for tactical lasers to be fitted to FJ for self protection, effectively burning out the sensors of incoming SAW and AAM, but the range to stand-off by a couple of hundred miles and take out an accelerating ICBM is something different.
Thought they haven't given up......
Missile Defense Agency Seeking A High-Flying Drone For "Airborne Laser 2.0" - The Drive