Interesting. They said, essentially, that "fighting the wind" decreases flight time.
I've actually found that hovering in, say, a 10mph breeze, INCREASES flight time...because a certain forward (or sideways, etc) flight speed is more efficient than hovering...just like in a helicopter.
Of course if it's a 25-30mph breeze, flight time will decrease...but the point is, at lower wind speeds, and compared to hovering, a bit of wind can actually INCREASE flight time.