It's cooler and saves fuel!
... and it confuses Air Traffic Controller.
Asking for permission to enter airspace Charlie at FL 100 in order to catch some nice tailwind (groundspeed of 170 kts in a B407) I had the following radio communication:
Radar: "... Could you please confirm your callsign is D-H...."
Me:"Affirm, callsign is D-H ..." (In Germany a callsign starting with D-H ... always indicates that you are a helicopter)
Radar: "D-H ... Could you please confirm you are a helicopter."
Me: "Affirm, D-H ... is a helicopter."
Radar: "We just had a little discussion here. FL 100 and a groundspeed of 170 kts just didn`t seem to be right for a helicopter."
