Thousands of passengers are being sold tickets for flights on Boeing aircraft that are still officially grounded after two crashes took the lives of 346 people.

TUI, United Airlines and other airlines have scheduled more than 32,600 flights on 737 Max 8 and Max 9 aircraft for later this year — although regulators have not yet approved their return to the skies.

One British tourist said he felt like a “guinea pig” when he discovered last week that his American Airlines flight to the Caribbean would be on a 737 Max 8. Chuni Kahan, a property manager from north London, had been told at the time of booking that he would fly on an earlier Boeing 737 model. He has been denied a refund.

Hundreds