Shuo says many of his student friends have been running around in circles since April trying to buy flights, then getting refunds. “I know airlines are not flying right now, but they are selling tickets, so you just have to bet on it,” he says. “What choice do we have?”

There were an estimated 370,000 Chinese students in the US in the 2018-19 academic year, according to the latest figures available from the Institute of International Education, though the number has fallen in the current academic year.

Many have rushed to escape the Covid-19 situation in the US, where more than 93,000 related deaths have now been recorded.

“You actually give up hope of ever getting the refunds. It’s not fair, because the United [Airlines] website keeps saying the refund request is ‘unprocessed’,” Shuo says.

“Before I got a refund I had no choice but to go ahead and buy another ticket. What are you meant to do? Your flight has again been cancelled, you want to get home. Many people are in the same boat.”

“I think it’s wrongdoing on the airline’s part,” he says by phone. “I feel terrible for travellers who got stuck overseas and have to pay for multiple tickets wishing one of them actually works. It’s not just United Airlines who is guilty of this; Delta, American are the same.

“This whole story started after United suspended flights to China, initially until April 24. A friend contacted me about his flight to Shanghai for May 19, a ticket he bought early in April. He was concerned his flight would be cancelled and that he wouldn’t be able to get a cash refund to book and pay for another flight.

“After checking the status, I could see from the flight schedule the company had uploaded for crew that there were no China flights on that date.

“Then I noticed that no pilots or flight attendants were assigned to that trip at all. As a matter of fact, the flight wasn’t even included on the May flight plan from the outset.”

The flight attendant says that staff memos and flight schedules shared with crew members point to discrepancies between routes offered to the public and those United actually plans to operate.

“At that point I checked our internal booking system, and was shocked to see the May 19 flight SFO to PVG [San Francisco to Shanghai] still there. That means travellers could still book that flight, even though it was not included in staff flight schedules.”

It gives the impression United has been intentionally selling seats on “phantom flights” – with planes that are not planned to ever take off, he says. “On May 2, for example, you [could] still book June flights from SFO to PVG even though that is not on our internal flight plan.

“Even though our CEO, Oscar Munoz [who this week steps aside to become executive chairman], has told us in a memo we will be down 90 per cent on scheduled flights in June, as for May, somehow you can still buy tickets to Shanghai, Singapore, London, Beijing. Yet in our bid packets [a computer program for crew scheduling] for May, the only two routes operating from our San Fran hub are to Tokyo Narita and Sydney.”

United’s website is selling tickets for the San Francisco-Shanghai route every day from May 29. United told employees in a memo in early May it would “pencil in four China routes in the June schedule”.

Those routes include San Francisco to Beijing, Chengdu and Shanghai Pudong, and Newark to Shanghai, with some tickets selling for US$3,200 one way. “We continue to work out the feasibility of restarting passenger service to China,” the memo says.

United Airlines has yet to respond to a request for comment on these matters, more than a week after email enquiries were sent by the Post.

“For United, as with other airlines currently offering flights to places that are in lockdown, maybe they are betting on the lockdown being over before the plane takes off,” says the United flight attendant. “Airlines are therefore guaranteed to have passengers ready to board as soon as the lockdown is lifted.”

If lockdowns aren’t lifted in time, he says, flights will just be cancelled, with any withheld refunds providing a money bank to cash-strapped airlines.

“Meanwhile they still have their much needed cash revenue, and technically, no regulations can prohibit them doing so for as long as they have those flight landing slots and route licences to operate.

“So it’s just a win-win situation for airlines. But I do think they should be more transparent and tell passengers those flight schedules may change due to Covid-19. There are no such warnings when you book. The bottom line is, most people think if airlines are selling the tickets, the plane will take off, but in reality there are some flights here that are just never going to take off.”

The United crew member hopes travellers will be able to sue airlines for “misrepresenting, and for damage caused by knowingly selling flights that will be cancelled”.

For his part, statistics student Shuo is not confident of finally boarding that plane home this month.

“I heard already that maybe United will not open that route until after May,” he says. “I don’t know if the flight will actually [take off], but I must try. I am aware of the airline situation, I know they are not flying right now. Maybe some routes will reopen. But we don’t want to give up … so we just pay for the future.”

Three days after talking to the Post, Shuo got in contact to say his May 26 flight had also been cancelled. Did the airline tell him? “No, I checked on their website myself. Maybe the next flight is May 28.”

Maybe, but Shuo hasn’t yet plucked up the courage to rebook.