Ryan Air (US version NOT Ireland's version) have been bringing narrow body Airbusses in from Europe for a few years, they used to use Airtours aircraft out of the UK, (dry leased I think). Also, Apple Vacations out of NYC used C-reg Canada 3000 A320's to fly US-Carribean routes (definitely Canadian crews). I also saw a G-reg Britannia B737 in Hawaii with Aloha Airlines markings, and that was way back in 1989, (Aloha crews operating domestic US).