The launch of the A321XLR at the 2019 Paris air show is pushing the range limits for narrowbody aircraft. Airlines will need to be very aware of passenger wellbeing, especially in economy class.

The A321LR provided a 15 per cent increase in range over the basic A321neo, reaching 4,000nm with three Additional CentreTanks (ACT) in the lower fuselage. The A321XLR adds another 15 per cent, or 600nm, pushing out to 4,500nm in typical two or three-class layout with around 200 passengers.

This has been achieved by fitting a new permanent Rear Centre Tank (RCT) carrying 12,900 litres of fuel. In a clever piece of engineering, the RCT holds the fuel volume of four ACTs; takes up the space of two ACTs; and has the weight of one ACT. The A321XLR can also be fitted with an optional forward Additional Centre Tank that adds another 200nm.

Of course, the new generation CFM LEAP-1A and Pratt & Whitney PW1100G-JM engines already provide 30 per cent lower fuel burn per seat than the A321ceo, giving an inherent range boost. More fuel means more weight, so maximum take-off weight (MTOW) has been increased to 101 tonnes, requiring a modified landing gear.

An optimised wing trailing edge flap configuration preserves the same take-off performance and engine thrust requirements as the basic A321neo. Airbus is suggesting that the cabin can be fitted with a two-class layout with fully flat seats in the premium cabin, or up to 244 passengers in single class layouts.

While it will incorporate various enhanced elements from the Airspace concept – XL overhead bins with 40 per cent more volume, ceiling lighting, new sidewall panels, a new lavatory design, new window bezels, coloured LED lighting for the cabin and wifi for passengers and crew.

That high density, all-economy configuration, will need some very comfortable seats; especially as the aircraft has been selected by no less than seven low-cost carriers, accounting for nearly 30 per cent of the order book. To give this some context, Airbus shows Miami to Buenos Aires as a possible route for the aircraft.

American Airlines flies this route with a Boeing 777 in a time of just under nine hours outbound, just over inbound. For Auckland to Honolulu, an Air New Zealand 787-9 takes just over nine hours. Another route is Sharjah to Cape Town. An Emirates 777 from nearby Dubai takes 9 hours 45 minutes to reach South Africa.

Bear in mind that both these aircraft will cruise at a slightly higher speed than the A321XLR, so those flight times could be longer. It does seem that one low-cost carrier is aware of the hazards of passengers being cooped up for long periods.

JetBlue says the A321XLR allows it to evaluate more overseas destinations, such as London and is developing a reimagined transatlantic version of its premium Mint product, as well as an enhanced transatlantic Core experience. However, chief executive officer Robin Hayes described the European market as suffering from high fares or mediocre service and effectively controlled by legacy carriers and their massive joint ventures.

That raises the bar for a comfortable cabin. Among the other customers, Frontier Airlines says the A321XLR will enable to it offer coast to coast services and explore exciting international and domestic opportunities, such as Hawaii.

Qantas Group chief executive officer, Alan Joyce, said the aircraft can fly routes like Cairns to Tokyo or Melbourne to Singapore, adding that there is plenty of potential across Qantas and low-cost carrier Jetstar.