On a Tuesday morning in July, departures to places that weren’t part of United’s regular rotation are displayed on the gate board at Chicago O’Hare. Dublin, Edinburgh. The speed at which an airline can determine that there are enough passengers on a particular route to warrant putting an aircraft on it is a kind of mundane miracle, and the network maps that emerge from hundreds of those decisions, compounded across carriers, end up influencing where people actually go on vacation without anyone specifically planning that outcome.
In an industry where individual percentage points of capacity increase translate into real money and real logistical complication, United Airlines is operating around 9% more capacity this summer than it did a year ago. The fact that O’Hare alone has 750 daily flights to 222 destinations provides an idea of the size of the business. The European additions—Croatia, Italy, Scotland, Spain, and Iceland—are deliberate rather than haphazard. Although these ideas are not brand-new for transatlantic travel, they do reflect particular wagers on where demand is concentrated and where direct service can attract travelers away from hub-and-spoke routes via Frankfurt or London.
American Airlines is using a different kind of scale to describe their summer. If everything goes according to plan, the estimated 75 million passengers on 750,000 flights between late May and early September would make it one of the biggest single-carrier summer operations in aviation history. The new European destinations, Budapest and Prague, which have both historically been underserved by direct transatlantic flights from US cities, are part of a larger trend in which airlines are searching for city pairs where there is observable latent demand that hasn’t been realized because widebody deployment economics didn’t previously support it.
The A321XLR becomes significant in that economic argument. The Airbus A321XLR is an extended-range narrow-body jet that can fly shorter transatlantic routes that would require packing a widebody aircraft, which is typically a riskier and more expensive option. The most obvious example of what the aircraft unlocks today is American’s Philadelphia to Porto route using A321XLR service: a city-pair connection between a mid-sized US market and a mid-sized European destination that could not have been economically served with previous equipment. The number of city pairs that are feasible for direct transatlantic service increases significantly as more A321XLRs are delivered by American and other carriers. Similar reasoning is extended into longer-haul regions from a major hub with the announcement of Dallas to Athens and Dallas to Zurich this summer.
It’s important to comprehend what goes on at the network planning level because it involves more than just adding flights where they currently exist. The expansion into markets like Budapest, Prague, Athens, and Porto, where a connecting itinerary via London or Amsterdam was previously the only option for an American traveler wishing to visit. Time is not the only benefit of direct service. It can encourage travel that a connection’s friction could have stifled and immediately competes with those connection hubs for the passenger’s routing choice. The industry refers to this phenomenon as “route stimulation.” When a new direct route opens between a US city and a European destination, booking volumes on that corridor typically rise above what the previously connected routing was carrying.
Booking data that airlines and travel agencies have been monitoring since late winter shows the summer that is being built around these route additions. The demand for leisure travel to European locations is still high, maintaining the momentum that developed during 2023 and 2024 as pent-up post-pandemic travel finally made its way through the system and created new baseline expectations among travelers who rediscovered and found reasons to continue taking international trips. It is genuinely unclear if that baseline will continue through 2027 and beyond, or if the current increased demand is a long-term post-pandemic effect or a permanent shift. With actual planes and actual gate slots, the airlines that are rapidly growing this summer are wagering that it will succeed.
