During World War II, a Pan Am flying boat found itself stranded in Auckland, New Zealand, unable to return to San Francisco due to Pearl Harbour's bombing turning the Pacific into a theatre of war.
From John Bull, The Lapsed Historian:
After the Japanese attack on Pearl Harbour, the crew of Pan Am flight 18602 were forced to do something almost impossible: return to America the long way round.
To get back the California Clipper would have to carve out an all-new route for flying boats from Australia to the East Coast of America. Years before, when the Pacific route had first been charted, it had been done in careful stages, with fuelling ships and stations carefully planned and placed months in advance, using a flying boat specially prepared for the purpose and with a bountiful supply of maps and charts.
The crew of the California Clipper had none of that — all they had was whatever they could scrounge up at Auckland and a commercial flying boat which, by the end of the trip, would have had to fly longer and further in a single trip than any Boeing 314 had ever managed before. They would be flying blind, and they would have to push themselves and — more crucially — their plane well beyond the limits of knowledge and safety.
The entire story is well worth a read (including parts two and three) and covers adventures including poor quality fuel, run-ins with submarines, and world records the public didn't know about for years.
This would make a fascinating Indiana Jones-style movie.
Cover image: Library of Congress via Wikipedia