UFO swooped in over our car and disappeared.

My daughter, her friend and I were traveling northbound on Rt. 309, going towards Quakertown, PA. It was approximately 9:30pm. It was a clear night and there were other cars on the road at the time. We had just passed the exit for Perkasie, PA (Rt. 563) when an object swooped in over our car, hovered for a second and disappeared. My daughter and I both exclaimed, "Did you see that?". Unfortunately, my daughter's friend, who was in the backseat, did not see it. It was not possible to determine the size of the object due to the brief encounter, however, it had one pale blue light on either end of what may have been its wings. Based on the location of the lights, it appeared bigger than a single engine plane. It blocked out the stars, so it was solid. The whole episode only lasted 1-2 seconds. If we had blinked, we would have missed it. The object disappeared in an instant and left no exhaust trail and it made no noise. My daughter and I are college graduates and never experienced anything like it before. I am a mental health professional and not given to flights of fancy.