Recollect seeing Pan Am 747s climbing out of Heathrow on a Dover departure, as I recall it was Clipper 1 which went eastbound around the world and Clipper 2 did the same westbound.
Another recollection of a TWA 747 trailing eastbound over Woodley into Europe around 1978 and seen from about 20 miles south; bloody great ball of vapour suddenly expanded from the trail, wondered if it was some kind of engine failure.