United Airlines is considering adding another destination in Europe from its Denver hub, following the success of the London Heathrow service it began this summer.

"We're hopefully going to add another international European destination out of Denver," says Scott Kirby, president of the Chicago-based carrier, at the Boyd Group International Aviation Forecast Summit in Denver.

The service to London, which began in March, has been a success in part due to the additional domestic feed that United has added in Denver in recent years, he adds.

Kirby is mum on what destination is being considered, though the Denver International airport offers up to $6 million in incentives over two years for any new transatlantic service.

London is United's largest destination in Europe, followed by Frankfurt and Munich – both bases for its joint venture partner Lufthansa – respectively, FlightGlobal schedules data shows.

"My guess would be a Star Alliance hub," says Laura Jackson, vice-president of air service development at Denver airport, on the sidelines of the conference. "Frankfurt is very strong [and] Munich is strong."

Her guess is a flight to Frankfurt, where United would benefit from significant connecting passenger flows with Lufthansa.

US carriers have focused on serving transatlantic partner hubs in recent years. For example, Delta's recent additions to Europe have been primarily to Amsterdam, London Heathrow and Paris Charles de Gaulle - bases for its partners KLM, Virgin Atlantic Airways and Air France, respectively.

Delta is scheduled to operate 61% of its capacity to Europe to its three partner hubs in 2018, schedules show. By comparison, United only operates nearly 37% of its European capacity to Lufthansa Group hubs.

In addition to London, Denver boasts nonstop flights to Frankfurt and Munich on Lufthansa, Paris Charles de Gaulle on Norwegian, and Reykjavik on Icelandair, schedules show. British Airways also flies between London Heathrow and the Colorado capital.

Source: Cirium Dashboard