...Bloody-minded optimists say... the climactic shake-out is finally upon us. Once the cleansing is done, the airlines will go back to being profitable and sustainable like "normal" industries. Don't bet on it. Airlines have shown an ability to mint short-term profits in an economic bounceback when demand grows faster than they can lay on more jets and gates. But that's not the same thing as being able to make profits consistently enough to pay back the capital invested in the industry. The airlines have never been able to do this, at least not since deregulation.... Airports, meanwhile, are local monopolies...