To cross the Atlantic between NA and Europe you need to be able to travel 138 minutes from an airport, although for almost the entire area it’s 120 minutes.

This is accomplished by having air strips which can take massive planes like A350s at remote places which can’t justify planes of that size normally like Newfoundland, Greenland and the Azores

While these are mainly there for military and temporary emergency use, in 2001 they were used far more - with dozens of planes landing at tiny towns like Gander and St. John’s in Newfoundland, places which only really expect a single large plane to land and refuel rather than 30 with passengers to accommodate for days.