talking about head and tail winds.. once I was on a flight from HKG-ORD on United. When the plane leaves NRT air traffic control and head to ANC, I heard the pilot chat with pilots on the other plane about the tail winds ....

pilot a: How's your tail wind Korean Air blah blah?
pilot b: 230km/h, how's yours United 896 at 330? (33000 feet I guess)
pilot a: 220km/h.

that's kind of fun.

I was flying at 1100km/h at that time on a 747.