During strange weather times, you'll see groups of transatlantic aircraft on the ground at Gander/Bangor/etc. going westbound to N. America b/c they couldn't make the fuel/payload/runway calculations work out economically, so they pick up fuel.

Many years ago I used to do the TW CPH-JFK run and had several Gander encounters in a row. The runway at CPH at the time was just too short for an economical payload w/ the necessary fuel load-out. So we stopped in Canada. The mixed blessing was that the E-bound flight was incredibly short - good b/c you're not cooped up so long, but it was too short to sleep much.

Plus, as others have noted elsewhere, if you have a really short E-bound flight, you may wind up circling the airport until customs opens up for the morning (hrrrumph, HEATHROW!)

Greg99
(a - not THE) Danville 1k
Greg