Watching fighter jets doing exercises at night always made me think of people claiming UFO's. Sharp turns, going in and out of afterburner, multiple aircraft, makes quite a show. With no reference for distance or scale on a dark night, it often looks like the planes are hovering and then just veer off at high speed. In reality they were just moving away from us and then went into a climb or turn.
At the air show in Ft Worth a couple weeks ago, they said they had one of the stunt planes doing night practice with the LEDs on and the local PD got hundreds of "UFO" calls.