[user104658]

A lot of the jets are (relatively) old and they cost multiple-millions to build. It's unrealistic to say that every airline must completely overhaul every single plane. The only real solution here, is to either overhaul a certain number of planes and then say that disabled facilities are only available on flights at certain times, OR to make sure the actual toilets themselves are up to standard on every plane, and have the seats nearest the toilet refitted to be suitable. That would probably mean the front and back rows, on most flights. The problem there being that there would then be a limited number of "disabled spaces" on each flight... so you might have a disabled person trying to book onto a flight that has plenty of seats left - but unable to as all the disabled seats are filled.

To make every flight entirely disabled-friendly is verging on impossible. You would have to widen the aisle significantly, and probably the leg space between seats... the initial cost would be in the billions, plus the ongoing loss of revenue year on year (more space = fewer seats). It's just not practical.

Really the best thing to do, would be to say that all newly manufactured jets must follow a code that includes being disabled-friendly from the ground up. Then the problem will phase itself out over time.