British Airways has told a Frenchman he is too fat to fly with the airline at 500lbs, saying it was unsafe to let him board the plane.
Kevin Chenais, 22, was visiting Chicago for medical treatment after a hormone disorder led him to balloon to 500lbs.
He has spent the last 18 months at the May Clinic being treated for the disorder and was planning to return to France so he could continue his treatment at home.
Speaking to CBS, his mother Christina said: "We blame British Airways because now they just leave us, and they brought us here.
"If they could bring him here with that problem in economy, there was a way to take him back by economy but just get him back home for his medical treatments to continue."
After a week in a hotel paid for by British Airways, the family took a train to New York then returned to France on board the Queen Mary cruise ship.
Speaking about Chenais, British Airways said: "We will always try to accommodate someone if it's possible and safe to do so.
"Our customer service team worked diligently to find a solution and have exhausted all options. Unfortunately it is not possible to safely accommodate the customer on any of our aircraft and the family has been offered a full refund.
"The British Airways team has been in regular contact with the family, providing guidance and support as well as exploring other options for travel. We have also provided hotel accommodation throughout.
"We do not discriminate against customers for any reason. We treat all customers fairly and where possible we do not restrict seating options.
"We would provide the option to purchase an extra seat to anyone who contacts us with concerns about seat width ... The comfort and safety of all our passengers is of paramount importance."
However, the 22-year-old said the airline's explaination was not good enough: "I'm sure a lot of big people like me or bigger cannot travel because they have the same problem," he told CBS. "This time before leaving I knew something would go wrong."
Earlier this year, Samoa Air became the first airline to start charging passengers by their weight. When booking, customers are asked to enter their details, including the weight of passengers, and the fare is calculated accordingly. They are then weighed at the airport to ensure they have paid the correct amount.
British Airways currently has no weight limits or restrictions in place, but advises customers to buy an additional seat for their own comfort if necessary.
Asked by IBTimes UK if the airline has any plans to change this, a spokesperson said: "We have no plans to change our current policy.