Fitted with CFM International LEAP-1A or Pratt & Whitney PW1100G-JM engines, Airbus advertises a 20% increase in fuel efficiency per passenger, with 500 nautical miles (930 km; 580 mi) more range, or 2 tonnes (4,400 lb) more of payload.

The timeline from development to first flight took 6 years, relatively short due to its nature as an improvement, as opposed to a clean-sheet designed aircraft.

The prototype was equipped with CFM International LEAP 1A engines, the aircraft, registered D-AVXB, was flown by test pilots Martin Scheuermann and Bernardo Saez Benito Hernandez.

The A321neo has a range of 3,995 nautical miles (7,399 km), with an MTOW (maximum take-off weight) of 97 tons (97 000 kg/213 848 lb), and its engine has 24,500–35,000 lbf (109–156 kN) of thrust.

The first A321neo, leased by GECAS, was delivered in Hamburg to Virgin America, configured with 184 seats and LEAP engines, and entered service on 31 May 2017.

Air New Zealand has at least seven A321neos in its 13 A320-family orders, increasing seating capacity by 27% over A320ceos currently used on short-haul international routes, mainly to Australia; the neos will be delayed until July 2018 for the A320neos and September 2018 for the A321neos with a new, higher density and some A320ceo leases will be extended for the interim.

[10] Well suited for 2,100–2,300 nmi (3,900–4,300 km; 2,400–2,600 mi) routes to the US west coast, Hawaiian's 189-seat A321neos are more efficient than the competing narrow-body aircraft and even have slightly lower per-seat costs than its 294-seat A330-200s.

[11] The A321neo is a narrow-body (single aisle) aircraft with a retractable tricycle landing gear, powered by two wing pylon-mounted turbofan engines.

[27] The first A321neo, leased by GECAS, was delivered in Hamburg to Virgin America, configured with 184 seats and LEAP engines, and entered service in May 2017.

[citation needed] To offer similar takeoff performance, pitch response to stick input is a rate-command to hit the 3°/sec rotation rate to capture the right pitch attitude and there is an "electronic tail bumper" preventing a tailstrike if the stick is less than three-quarters of the way aft; additional thrust, slower rotation and lift-off speeds require more rudder authority and its maximum deflection went from 25° to 30°.

[31] A stretch would probably involve fore and aft plugs to keep its centre of gravity, but tailstrike clearance could constrain field speed and performance, and a larger aircraft could require more powerful engines, while further cabin crew would be needed over 250 seats.

[34] In October 2014, Airbus started marketing a 164-seat, 97 t (214,000 lb) MTOW variant with three auxiliary fuel tanks called the A321neoLR (Long Range) with 100 nmi (190 km; 120 mi) more operational range than a Boeing 757-200 configured with 169 seats, 27% lower trip costs and 24% lower per seat costs; it was scheduled for introduction in the second half of 2018, two years after the A321neo.

[38] Certification was aimed for the second quarter of 2018, with a programme including tests with one, two, three, or no additional centre tanks and a transatlantic flight on 13 February.

[42] On 13 November 2018, Arkia received the first A321LR, featuring 220 seats in a single-class and to be deployed to London, Paris, Barcelona for up to 5h sectors, or to Zanzibar and the Seychelles, saying it is the first narrow-body more efficient than the 757-300 it operates.

With a lower-density cabin, it was expected to fly almost 5,000 nmi (9,300 km; 5,800 mi)[19] It was to cover more of the market segment likely to be targeted by the Boeing 797.

[47] In November, Airbus indicated that the A321XLR would have a MTOW of over 100 t (220,000 lb) and 700 nmi (1,300 km; 810 mi), more range than the A321LR with the same wing and engines, increased fuel capacity and strengthened landing gear.

[48] In January 2019, Air Canada expressed interest in using narrow-body aircraft for transatlantic routes and said it was considering options including the A321XLR and the Boeing 737 MAX.

[50] Its design offers 4,700 nmi (8,700 km; 5,400 mi) of range and features a new permanent rear centre tank (RCT) for more fuel, strengthened landing gear for a 101 t (223,000 lb) MTOW, and an optimised wing trailing-edge flap to preserve take-off performance.

[52] As the sharklets lowered take-off and landing speeds, the switch from a double-slotted to single-slotted inboard flap will reduce complexity, weight and drag.

[55] IAG quoted a $142 million list price as it committed to 28 aircraft, including eight for Iberia, six for Aer Lingus, plus 14 options.

[56] Qantas Group placed an order for 36 XLRs, to be operated on routes between Australia and Asia, and is also set to be one of the launch customers.

[64] On 3 December 2019, United Airlines announced an order to purchase 50 new Airbus A321XLR aircraft, with deliveries beginning in 2024, to replace their Boeing 757–200 fleet.

[65] Valued at $7.1 billion before discounts ($142M each), United plans to use these aircraft for additional destinations in Europe from its East Coast hubs in Washington and Newark, New Jersey.

[70] In July 2024, the Airbus A321XLR powered by CFMI LEAP engines received certification from the European Union Aviation Safety Agency (EASA) and conducted a demonstration flight at the Farnborough Airshow.

[67] By August 2020, Premium Aerotec had started producing the rear centre tank for the first A321XLR in Augsburg, to be transferred to Airbus's Hamburg plant in early 2021.

[72] By April 2021, a standard A321LR fuselage section had been withdrawn from the Hamburg production line for use as a "pre-industrial system accelerator" to test the integration of XLR-specific systems; at Saint-Nazaire, a nose section was serving as an integration test bed for a new instrument panel assembly, before being used to analyse structural reinforcements needed for the XLR.

[73] By then, Airbus had completed the first centre wing box 16 months after the first metal cuts, with 200 modifications from the standard design, delivered from Nantes to Hamburg for structural assembly.