Are you sure that there's not an "if" in the text? (e.g. "If you will be transiting via the USA . . . ").
Otherwise, like you, I'm confused! An aircraft that was able to fly directly to Wellington would need to head roughly NNE from London, whereas an aircraft destined for Singapore would need to head roughly ENE.
To get to southern USA, an aircraft would need to head roughly West, whereas to get to Alaska it would need to head roughly NNW.
So it doesn't make sense to me either!
https://www.mapability.com/ei8ic/maps/great_circle/capital_cities/london_uk_great_circle_map.php
Flight numbers?