Airbus A321 (A321)

The Airbus A321 was the first stretch of the A320, launched in November 1989 once the original aircraft had proved itself and airlines asked for more seats on the same cockpit. Airbus added two fuselage plugs, 4.27 m ahead of the wing and 2.67 m behind it, for a total of 6.94 m, which took the cabin from about 150 seats to roughly 185 in two classes and up to 220 in one. To carry the extra weight the wing gained double-slotted flaps, the landing gear was strengthened and the engines moved up to higher-thrust versions of the CFM56-5B and IAE V2500.

The first A321 flew from Hamburg on 11 March 1993, and Lufthansa began services in early 1994. It was also the first Airbus assembled in Germany rather than Toulouse, the start of the Hamburg final assembly line that would later build most of the family. The initial A321-100 had limited fuel capacity and range, and sales were modest until the A321-200 of 1996 added an extra centre fuel tank and higher weights, lifting range to around 3,000 nautical miles and making it a credible 757 replacement.

That replacement role defined the aircraft's second decade. As Boeing ended 757 production in 2004 without a direct successor, the A321 became the largest single-aisle on the market, and US carriers that had flown 757s on dense domestic and Caribbean routes turned to it: American, Delta, JetBlue and United all built large fleets. American and JetBlue went further, fitting lie-flat business or Mint seats for transcontinental premium service, something no other narrowbody was offering.

The re-engined A321neo of 2017, with its LR and XLR long-range versions, completed the transformation into a transatlantic aircraft, and the A321ceo ended production around 2021. Freighter conversions have since given many early A321s a second career with express operators.

The A321's structure is the A320's with reinforcements: the fuselage plugs are standard frames, but the wing centre section, keel beam and landing gear were strengthened for a maximum take-off weight that grew from 83 to 93.5 tonnes across the -100 and -200. The most visible aerodynamic change is the double-slotted trailing-edge flap, needed to keep approach speeds reasonable at the higher weights, where the A320 and A319 use single-slotted flaps.

Unlike its siblings, the A321 has no overwing emergency exits; instead it carries four full-size doors per side, with the second and third pairs ahead of and behind the wing. On later aircraft Airbus offered the Cabin Flex layout, which deletes one door pair in favour of overwing exits and allows up to 240 seats on the neo. The cockpit, fly-by-wire system and sidesticks are identical to the A320, so the whole ceo family shares one type rating.

American Airlines and Delta operate the world's largest A321ceo fleets, using them on dense domestic trunk routes and to Hawaii and the Caribbean; American's transcontinental A321T carries lie-flat first and business seats. JetBlue, United, Spirit and Frontier fly it in the United States, while in Europe Lufthansa, British Airways, Aer Lingus, Turkish Airlines, Wizz Air and TUI use it for leisure and trunk routes of up to four or five hours. Asian operators include China Eastern, Philippine Airlines and Vietnam Airlines. With the A321neo replacing it on front-line routes, many ceo airframes are being converted to freighters for carriers such as Qantas Freight and SmartLynx.

An A321 is a long walk from the front to the back, but the cabin is the familiar A320 cross-section, so the seats are the same 18-inch width in a 3-3 layout and the aisle is wider than a 737's. Airlines use the length very differently: American's transcontinental aircraft have lie-flat first and business cabins, JetBlue fits Mint suites on premium routes, while leisure carriers pack in 220 seats at 28–29 inches of pitch. Because the engines are far forward relative to the long rear cabin, the last rows are quieter than on a 737-900 but feel the tail's movement more in turbulence. The absence of overwing exits means no exit-row legroom in the middle of the cabin; the extra-legroom seats are usually at the bulkheads and the doors. For the best seat, choose a window a few rows behind the wing on a two-class aircraft, and avoid the final two rows, which back onto the lavatories and may not recline.

The A321 is the long one. Against the A320 it is almost seven metres longer, with four full-size doors per side and no overwing exits, which is the quickest check: if you see two full doors between the wing and the tail, it is an A321. The double-slotted flaps, visible as a second hinged section when extended, are another distinguishing detail. Telling a ceo from an A321neo is harder: the neo has much larger engine nacelles (the LEAP-1A and PW1100G fans are a full metre across) and Sharklets as standard, and many neos use the Cabin Flex door layout with overwing exits that no ceo has.