Well, my guess would be kind of a groupshare idea. Someone posts something somewhere like "going to LA soon, who wants in?" If the poster gets critical mass, then the poster contacts a provider and says "I got this many people for LA". Discussions ensue as to fare and when and possible return flight. Essentially a chartered flight. Sounds cumbersome but if it became the norm I'm sure apps and whatnot would fill in the inconveniences (and attract competition, from other providers as well as other modes of transport. Heck, I'd sleep in the back of a moving truck if I could get to my destination cheaply.)