I was walking in a park in a city with someone amongst some other people, and there was a bright large flash of moving light in the sky right overhead (maybe 500 to 1500 feet up?), moving so fast that it was only there for a fraction of a second, and made no sound, like a hallucination or very brief flash of light, except the person i was with saw it too. Most other people around us however acted like they had not seen it, as far as we could tell, or like they didn’t register it or thought it was not actually something.