the more business ($, SFr, DM, etc) a company brings to an airline, hotel, car-rental, etc. company the better price they will achieve (rebates/discounts) - that's already the case today.

and as a recompensationfor what the fflier endures (and that's measured by time/distance/and class) he gets some miles for future upgrades or trips in his free time.

I think this is fair and reasonable for all involved parties: those who pay get a better price, those who suffer get some comfort, and the airlines are more likely to have full flights.

The discounted eco-traveller contributes too to the comfort of business-class- and first-class-travellers. Only because of so many people who can afford today to fly (in eco) are the airlines able to provide such a big choice of offers to the business-people (more choices/options like flight times, direct flights, connections, etc.).