Speaking of Halifax, wasn't this the airport and area that showed all that hospitality to Americans on 9-11?
I think so. It would be a likely candidate, too, being on the great circle flightline to England/France.
You're thinking about Gander, Newfoundland, where the locals basically showed up at the airport with offers of food and lodging. I'm sure Halifax saw some diversions as well, though. Maritimers are some of the kindest folks you'll ever meet anywhere. As they say, there are no strangers, only friends you've yet to meet.