2 links have been added on this idea.
  1. Southwest Airlines let you choose your seat size before flying, which is probably what other US airlines should do.

  2. A London based design firm designed seats that could be adjusted to fit oversized passengers, but this just means making everyone pay for the gap in between. This doesn’t seem to solve the problem because now thin people will pay the price and overweight people will still splill into their allotted space, so agreed, someone needs to solve this problem still.