The treatment of disabled passengers by four of the UK's seven busiest airports is unacceptable, the aviation regulator has warned.
London Gatwick, London Stansted and Birmingham were told that they "need improvement" while Manchester was the only airport to receive a "poor" accessibility rating from the Civil Aviation Authority (CAA).
Officials at London Gatwick and London Stansted failed to provide the regulator with sufficient information about the standard of service at their airports.
London Heathrow, the UK's busiest airport, was one of 26 airports classified as "good" or "very good" this year. It was among four rated "poor" in last year's study.
Disability charities welcomed the improvements made in recent months but expressed concern that several of the largest airports were continuing to fail on accessibility.
Neil Heslop, chief executive of Leonard Cheshire, said "it is not acceptable" that some major gateways to the UK remain poor for their treatment of passengers with disabilities.
Phil Talbot, head of communications at disability charity Scope, urged the CAA to "continue to work with airports to bring those lagging behind up to scratch".
CAA data shows that more than three million requests for assistance are made at UK airports annually, up almost 80% since 2010. Some 83% of these passengers say they are "satisfied" with the service, and 54% are "very satisfied".
Aviation Minister Baroness Sugg called for passengers with reduced mobility or hidden disabilities to "get the service they deserve every time they fly".