KLM/Privatair do AMS - Houston B738, but then again premium low density seating high fare paying pax paid for by their employer. I thought LH used to do/ was doing something similar from DUS to USA. Now that would be a different ball game for RYR. But why not? If they could undercut these major carriers at their own game and offer similar service at 30% discount from STN, MAN, DUB, CDG, MAD, AMS, GLA/EDI, BFS, LIS, TOU, NRN, EIN, perhaps there is a successful business plan to be had. Is there a will? Perhaps there is a way.
I'm not suggesting they 'should' do it, I just question if it might be feasible with dedicated a/c, and cabin crew.