Fast streaks in sky

I've noticed twice in last month a streak of something flying super fast through the sky. It's a light gray color and goes so fast across that is seems to create a line as it moves then disappears in a flash.

I urge others to just look up at the sky late at night and see if you notice streaks like this. I think these would be seen with an infrared camera better. I was looking West, toward Florida's western coast. But I bet this happens in other places.