Recently I was stuck on a plane on the tarmac for one and a half hours waiting for the lift that takes people off the plane, who can't get down the stairs. One woman got so fed up she went down the stairs on her bum.
None of this is unusual. We have to book accessibility services ahead of time, get to the airport in plenty of time, and yet still there is often lots of waiting around because they have not organised enough staff to provide the service. It's staffing, when we left the plane we could see three lifts not being used, so they obviously were short staffed.
Disabled people pay for their tickets, but are expected to just put up with a standard of service that would lead to outrage if able bodied people had to put up with it. Imagine if planes routinely sat on the tarmac for up to a few hours before they brought the steps to the plane.