They do not (on a scheduled basis). It is difficult for any airline to dedicate an aircraft or two for a given route, because of aircraft interchangeability and rotations, I can't see the Y/Y+ only scenario. Should the LCC come to fruition, 777's at this point are not included in the fold.

Higher density could mean many things. I could include yanking out the stand-up bar and installing another row of J/C seats. Who knows?

Having said that...nothing is a given.