Passenger assistance is ultimately paid for by everyone’s air fare.
it’s provided by airports purely on a self cert basis. I have never been asked for proof of my disability when travelling (and brutally there is no such thing as a disability card that is valid across the whole world - who would issue it?)
there was a big boost given to passenger assistance with the Americans with disabilities act in 1990 which required accessibility adjustments in both profit and non profit organisations.
American airports and American airlines and in fact any airline that flew to America was expected to make adjustments.
i have been to America and they are genuinely so far ahead in accessibility requirements it’s untrue.
Over there disability rights are strongly associated with veteran’s rights - so people who have fought in the American army - and there’s a real attitude of respect that seems to carry over to disabled people generally.
I was at a Walt Disney park on Veteran’s day and there were so, so many disabled people there wearing their army stuff (don’t think it was quite uniform) and genuinely random people were just going up to them and saying thank you for your service.
made me feel that you know sometimes the Americans do get something right.
so yeah, airlines pay a ground handling fee to the airport and that covers all the airport services including passenger assistance.
in any given 5 minute slot, yeah there’s a limit on passenger assistance. But in a say 8 hour slot there isn’t.
and realistically the airport prioritises as best they can. I’ve sat on a plane for over an hour (and it missed its slot for the next people) because an ambilift was broken at Stansted. That delayed a whole plane full of people. But I can’t walk off a plane no matter how much people want me to.
the airport will have a priority system for stuff like ambilifts.
if you are taking staff, then the obvious thing to do if you are short of staff is prioritise departing passengers and let arrivals wait.
we’ve all seen similar when there’s horrendous queues at security - they go through pulling out people whose flight is going asap and get them through fast.
so, in conclusion, more people with disabilities flying means: more staff on shift, if there’s a temporary shortage of staff they’ll prioritise, and the cost of these staff is included in ground handling charges that the airline pay to the airport.