Has anyone else seen the little thing that flies behind the 737 IRL? In a lot of programs with the 737 in it, I have seen a little black thing on the end of a wire hanging off the vertical stabalizer and was wonndering what the hell it is.Any ideas?

I think I know what you mean, it looks like a very small brake parachute but it

Its a High Speed Trailing Static Tube, its for calibrating the aircrafts static ports(true ambient pressure at the flight level) without any disturbances from the body of the aircraft.The drogue is for stability while being towed on the test aircraft.