Becky Morton is a news correspondent for the British Broadcasting Corporation.
If airports fail disabled passengers, they could face enforcement action.
Some recent incidents were unacceptable according to the Civil Aviation Authority.
It said that in some cases disabled passengers were left waiting for help to get off the plane.
In the last few months, the industry has struggled with staff shortages.
Thousands of jobs were cut by airlines and airports during the Pandemic.
Due to the return of demand for flights, it's hard to recruit and train new staff fast enough, leading to delays and cancelations.
The assistance was being provided in a timely manner for the vast majority of passengers, according to the letter.
It was disappointing that there had been a dip in performance at some airports, with more disabled and less mobile passengers having to wait longer for assistance than usual.
There have been reports of passenger's wheelchairs not being unloaded in a timely manner and disabled people being helped off planes hours after other flyers.
The cause of the increase in demand for assistance services at some airports was not known.
All airports with a high number of passengers using assistance services will be asked by June 21 what they have done to stop service failures in the future.
"If these significant service failures continue, we will consider what further action is needed, including using enforcement powers," it said.
Manchester blamed staff shortages for the apology.
Frank said such situations were becoming depressingly familiar.
The airports seem to be moving in a different direction. He said earlier this week that the level of investment and effort that goes into making money at these airports isn't matched by the amount of money needed to get disabled passengers off the plane.