Earlier this year, JetBlue Airways (JBLU 1.83%) finally pulled the trigger on converting 13 A321neo orders to Airbus' (EADSY 2.23%) new A321LR, a longer-range variant of the same plane. The A321LR has enough range for some transatlantic routes, and JetBlue plans to use the planes to fly to London from New York and Boston, starting in 2021.

However, JetBlue is already looking for a plane with even more range so that it will be able to expand farther into Europe. Not surprisingly, the popular low-fare carrier is one of the first potential customers for the extra-long-range A321XLR model that Airbus is expected to launch as soon as the Paris Air Show later this month.

Airbus goes transatlantic with the A321LR

When the A321 was first delivered a quarter century ago, it didn't even have enough range for transcontinental flights within the U.S. However, Airbus improved its range over time, mainly by increasing the A321's maximum takeoff weight (MTOW), enabling more fuel to be loaded.

More recently, the addition of fuel-saving "Sharklet" winglets and the upgrade to new engines for the A321neo version have further extended the type's range. Today, a standard A321neo easily has enough range to fly between the U.S. West Coast and Hawaii with a full load. That said, most routes between the East Coast and Europe are significantly longer, making the A321neo unsuitable -- particularly for westbound flights that can face stiff headwinds. For this reason, Airbus rolled out the A321LR several years ago.

An Airbus A321LR parked on a tarmac, with air-stairs attached.

The A321LR has 4,000 nautical miles of range, according to Airbus. Image source: Airbus.

Thanks to extra fuel tanks in the aircraft's cargo area and an increase in the MTOW from 93.5 tons to 97 tons, the A321LR concept adds hundreds of miles of range relative to a standard A321neo. Airbus advertises the A321LR's range at 4,000 nautical miles -- sufficient for the vast majority of routes between the East Coast and Europe.

In reality, more range is needed

Despite Airbus' claims, the A321LR can't really be used on routes up to 4,000 nautical miles. The manufacturer's calculations assume very basic (i.e., lightweight) seats and cabin amenities and no headwinds. Under more realistic assumptions, the A321LR's effective range is much lower.

Indeed, United Continental uses the older Boeing 757-200 -- which has a similar stated range -- on many transatlantic routes. However, it stopped deploying the 757 for missions like its 3,470-nautical-mile Newark-Berlin route several years ago, as the westbound flight needed unscheduled fuel stops too frequently during the winter (when headwinds tend to be the most severe).

Worries about the true range of the A321LR were one big reason why JetBlue waited so long to commit to transatlantic flights. As a result, the carrier has been interested in the possibility of an even longer-range A321 variant for quite some time.

A JetBlue Airways Airbus A320 preparing to land.

JetBlue only operates within the Americas today. Image source: JetBlue Airways.

With the A321LRs it has already ordered, JetBlue could certainly add flights from New York and Boston to other destinations in the U.K. and Ireland. Routes like Boston-Paris, Boston-Amsterdam, and Boston-Madrid should also be feasible, as they are similar in distance to the New York-London route that JetBlue is already planning. By contrast, JetBlue has hinted that the latter group of cities may not be reachable from New York with the A321LR.

The A321XLR's MTOW is likely to exceed 100 tons. That will give it substantially more range than the A321LR, which has a 97-ton MTOW.

More international flights would boost JetBlue in Boston and New York

Adding flights to London makes a lot of sense for JetBlue, as that is the top business destination in Europe as well as a major tourist destination. The new London flights will make JetBlue more attractive to New York- and Boston-based business travelers in particular.

That said, there is ample demand for flights to many other cities in Europe. Aside from Paris, Amsterdam, and Madrid, which may be reachable from Boston (but not New York) with the A321LR, these include business destinations like Zurich and Frankfurt, Germany, and leisure-oriented destinations like Barcelona, Spain, and Oslo, Norway, that are even farther away.

JetBlue has a shot at becoming the dominant airline in Boston -- and more of a contender in New York -- if it can offer flights to most of the top European destinations in addition to its existing domestic service. The carrier has every reason to pursue these opportunities. Airbus' A321XLR will have the extra range that JetBlue would need to make these routes feasible.

Airbus executives have hinted that the A321XLR won't become available until 2023 or 2024. However, that should be just fine for JetBlue. The carrier has enough expansion opportunities within the U.S. and parts of Europe that are reachable with the A321LR to keep it busy for the next five years. Expansion deeper into Europe can wait until the mid-2020s.