The one shining gem across the pond seems to be Houston. It's now carrying well over 100 pax per flight and that number is growing each month. Who knew there was such demand for what I class as quite a niche route, seems to get a fair few on other forums scratching their heads as to where the traffic is coming from!
There's seems to be a fair few numbers connecting from IAH onto Flybe's Scottish routes, especially ABZ for obvious Oil related industries.