At M.85 and M.8, a trip that takes 10:00/10:38 hrs means the planes are 0:38 or 6.3% apart.
With a M.2 headwind, really big but not unheard of, the flights could take 13:05/14:10 hrs and are 1:05 and 8.3% apart.
Real differences are smaller but that's the idea.
(All theoretical, of course)
Last edited by CPRich; Dec 23, 2011 at 9:58 am