Airlines sell seats on Boeing's still blocked 737 MAXs

Airlines sell thousands of seats aboard Boeing's 737 MAX aircraft.

American and United are among the airlines planning to use them for more than 32,600 flights later this year, according to the Sunday Times in London.

A British tourist said he felt like a "guinea pig" when he learned that his flight from American Airlines to the Caribbean would be by one of the planes. When he bought his ticket, he was assured that another plane would be used and that the airline had refused to refund his ticket.

The aircraft were removed from service after two fatal collisions in a few months. A "travel intelligence specialist" told The Times that carriers have begun reintroducing planes in the upcoming schedules.