The Competition and Markets Authority (CMA), and the Civil Aviation Authority (CAA) have issued warnings as airlines struggle to keep up with a surge in demand after the pandemic.
It also follows a string of supply chain pressures in relation to fuel, and staff shortages.
Carriers have also been put on notice for not supporting customers whose flights have been cancelled.
The CMA and CAA believe some airlines are creating “harmful practices” by not offering appropriate compensation.
Authorities are pushing for airlines to offer alternative flight options, better communication, and refunds for some affected passengers.
The regulators say some carriers are performing better than others, while others are lagging behind.