I think what the airlines could do is take an approach similar to what energy companies currently do by teaching people how to save energy - work out ways to actually reduce the need to travel so much. The first place I would target is of course business related travel - a lot of which is plainly not necessary as there are alternatives out there. So - research your passengers, research why they travel, research what alternatives would appeal to them, invest in alternatives, make money.
Bear in mind that a lot of the SLF who actually have to undertake these ridiculous flights will love you for it. Next year I'm probably going to be flying to Australia for a 3 or 4 day business event. Yes - 48 hours flying time, massive jet lag to demo some software - because the videoconferencing facilities at our offices are 'poor' and management generally thinks videoconferencing is not quite there yet.
Wouldn't it be great if - for say 50%-75% of the total trip cost I could go to the Qantas Business Center in London, my Australian colleagues likewise in Sydney - and enjoy the latest state-of-the-art holographic Hollywood style videoconferencing, the latest state-of-the-art environmental control stuff to alleviate the time zone difference, and the latest state-of-the art features I can't even think about but the engineers who one day build this solution will need to come up with.
Don't haul people - bring them together.
You did ask for out of the box thinking ;-)
Regards,
Golf-Sierra