For me it's the opening sequence of 'Always'.
It's an idyllic lake scene with two guys fishing from a boat and sort of snoozing the afternoon away.
After the establishing shot has been on screen for a good few seconds right in the distance appears a PBY5 water bomber, descending, and heading directly for the boat.
As you may know these are used to fight forest fires in the States, and they pick up water by scooping it from the lake whilst in flight......