Very much a horde favoured BG.
A Druid, with parachute, Dashes, in Cat form, off of the impressively high alliance base. Lands very near, if not in, the river. GCDs into fish form with the glyph, of course. Said druid proceeds to swim up river at epic ground mount speeds while able to shift out of any slows at the drop of a hat.
Time elapsed from flag pick up to delivery, approximately 45s.
Alliance can get a fast flag snatch with an aquatic Druid but the last half is a foot race.