This looks like an early operational test of the Defiant, with a ground-launched sounding rocket as a surrogate Klingon:
I am imagining a 747-type aircraft in a ground support role, picking off targets on the ground, and untouchable by anything but gunfire, as the bullets would be too numerous, small, and fast to engage with a laser. At least early on. The plane simply flies high enough to avoid small arms fire, and literally toasts targets on the ground.
Pardon the expression;"Smokin', dude!"