We have seen the run flat technology on skid steers for years and recently on a Polaris ATV.  It will be just a matter of time before all wheels go airless.  John Deere and Michelin have introduced the Tweel.  Say goodby to flats.  The only bad thing I can see about this technology is the cost to replace the Tweel when it wears out.  Check out John Deer for more info.