I just had a game where the Chinook was halfway across the ocean, running at best speed, and had to turn back. Right as it was getting back to base...the city was nuked. My troops could've handled it, the Chinook could have gone bingo and resupplied from friendly ground forces, but we had to abort.
You can tell your interceptors to ignore the low fuel push, finish combat, and ditch--for the sake of one UFO--but you can't tell your dropshop to risk it all for the sake of an entire city.
Suggestion: Pop up a box--ONLY when enroute to a terror mission, you wouldn't throw away your troops on just a regular landing--when the Chinook reaches 50% of its total range.
"Commander, if we keep going--whether or not we make it to the city--we won't have enough fuel to make it back. If we push on and don't get there in TIME, I hope you have a SAR crew on standby."
"Continue" / "Return to Base".
If the player elects to continue and the nuke timer runs out:
The dropship immediately turns around and heads to the closest base (if only one base, home base) until the fuel runs out, then it crashes. If this is over the sea...that's unfortunate. If it's over land, there's a chance of generating a crashed-dropship mission type--IF Xenonauts supports it. The country takes only half the usual financing penalty, because HQ did absolutely everything they could to get there in time, ending up sacrificing a squad of soldiers and a dropship...much, much more reassuring than "The bastards didn't even try!".
If the player elects to continue and succeeds in the mission, temporarily give the dropship enough fuel to make it in a straight line back to the nearest base. It got there on fumes and favorable winds, it can get back in the same way. Apply a funding bonus. "They ran their equipment almost literally into the ground to get to us, thank $Deity they care."
If the player elects to continue and is defeated, nothing changes.
If the player elects to continue and aborts mission, treat it as a defeat. That dropship ain't moving, and the soldiers would probably be occupying the transport like the pilots in Blackhawk Down, trying to hold off the mobs until the bitter firey end.
It just really stung having to see that 'you didn't get there in time' message when there was fuel (barely) to make it and time (barely) likewise. If players want to elevate the stakes--the entire squad against the clock / a funding bonus--that could be a valuable hard-choices option.
What do you think, sirs?