I am an airline pilot and can tell you that Raptor is correct. Our climb speeds and cruise speeds, therefore fuel flows, are higher when flying into a headwind. Our Flight Management Computer automatically uploads flight data from our dispatchers who build the flight plan. Fuel efficiency, a.k.a. dollars, is everything so going faster into the wind minimizes fuel burn. On the 737, we cruise .79-.80 mach westbound and .74-.76 mach eastbound, give or take a little depending on flight length.