Not to sound skeptical, but I've seen some stuff Ratheon was putting out at least 10-15 years ago and I think it had some pretty impressive optical sensors. Are we including the various infrared frequencies?

Optical and infrared sensors have improved a lot and can be a useful supplement but due to limited field of view and interference from weather you generally can't count on them for primary search. Unless the target is really time sensitive, B-2 mission planners try to fly at night in bad weather when those sensors are seriously degraded.

I doubt it. If people are able to photograph dark birds at night, I see no reason why a missile with much bigger optics and more efficient (wider band and monochrome) sensors wouldn't be able to find a plane.