An estimated 6.6 million passengers are denied boarding by airlines around the world annually, despite having valid tickets, passports, and travel documents, due to overbooking, according to a survey by the Welsh insurance comparison company Go.Compare.

Using Civil Aviation Authority figures and survey data, Go.Compare said its findings showed that at least 20.9 million passengers annually were found to have been impacted by airlines’ overbooking over the last 10 years.

The report noted that a third of the 20.9 million passengers, totalling approximately 6.6 million travellers, told the comparison site that they were unable to board their flights as a result of overbooking despite having valid travelling documents.

Among the total travellers surveyed by Go.Compare, 84 per cent of those who were unable to board their original flights were booked onto different flights, which equalled an estimated one million passengers annually whose journeys were not rearranged.

Meanwhile, almost two-thirds of these few passengers reported that they lost money as a result of overbooking, but only less than half of them decided to claim their travel insurance despite airlines being legally mandated to provide compensation and assistance to travellers in these scenarios.

“Flight overbooking happens more than we’d like to think, and it can make for an extremely stressful start to any trip for the passengers affected,” Rhys Jones, travel insurance expert at Go.Compare said. “If it happens to you, and you’re not allowed to board a plane, the first thing you should do is confirm with the airline that you were denied boarding because of overbooking. Get this in writing if possible.”

He added, “Next, you’ll want to discuss what your airline intends to do to get your trip back on course, how they plan to assist you and what compensation they’re offering. They should try to book you onto another flight when possible.

“Remember to keep all relevant documents like boarding passes, communications from your airline and receipts for accommodation or meal costs. Your airline should compensate for these expenses.”