United to add blocked-middle seat option on A321XLR economy cabin

United Airlines confirmed it will equip each of its new Airbus A321XLR jets with a single row of economy seats in which the middle seat remains unoccupied, offering passengers the choice of a window or aisle seat with an extra tray table in the vacant spot. The airline describes the configuration as an enhanced version of its Economy Plus product, providing additional legroom.

The seats are expected to appear on all 50 A321XLRs the carrier has ordered, with the possibility of extending the offering to other aircraft in the future. United also plans to install new Polaris business-class suites with sliding privacy doors and a premium-economy cabin on the same jets.

"We're investing nose-to-tail across our fleet and giving customers choice and value in every cabin," United chief commercial officer Andrew Nocella said in a statement.

United said it will staff five cabin crew members on most transatlantic flights, matching the staffing levels used on the Boeing 757 it is replacing. Under FAA rules, the airline could reduce the crew to four on some flights if it chose to limit the passenger count to 150.

The move follows United's recent rollout of other economy upgrades, including a "Relax Row" that converts three seats into a flat-lying space on its larger long-haul aircraft and a walk-up snack bar for economy passengers on the A321XLR.