The Hong Kong-based Cathay Pacific is considering hosting internet auctions – in a similar way to eBay – in a bid to boost revenue and fill seats, the South China Morning Post reports.

“Customers would be invited to place an offer for their booked flights via a website prior to their departure date,” said a spokesman. “If their offer was successful they would be advised around four days prior to departure and the offer payment collected.”

It could mean passengers are able to fly in premium economy, business class or first class for less than usual, and would help the airline fill its planes. The move could irritate frequent fliers, however, who are usually the first to be offered a free upgrade when premium seats are unsold. It could also deter passengers from paying the full premium fare up front.

Several airlines already host upgrade auctions on selected flights, including Virgin Atlantic, Etihad, El Al, Air New Zealand and Austrian Airlines.

Last year Telegraph Travel detailed the easiest way to get a free upgrade as part of our Travel Truths series. Being a frequent flier was among the most effective, we found.

“It is sometimes necessary to upgrade customers,” said a British Airways spokesman, at the time. “This is rare and will normally apply to frequent flyers who are members of our loyalty programme first.”

A spokesman for Lufthansa added: “Passengers who paid more for their tickets are more likely to be upgraded than passengers who bought a discounted ticket. The frequent flier program status is also taken into account.”

Other ways to boost your chances include travelling on busy routes, travelling alone, simply asking, having a good reason – such as being exceptionally tall, pregnant, or celebrating a honeymoon – or having a faulty entertainment system.

Photo Credit: An airport apron controller vehicle is pictured in front of a Cathay Pacific Boeing B747-400 Aircraft on the runway at Frankfurt's airport February 21, 2012. Alex Domanski / Reuters