In total, these aircraft will feature 161 seats: 20 Polaris suites, 12 Premium Plus seats, and 129 economy seats. While it's not been confirmed, it's believed that United is using the Elevate Altitude, a direct-aisle access lie-flat seat herringbone with privacy doors, similar to the products featured on JetBlue's Airbus A321LRs and American Airlines' Airbus A321XLRs. The difference is that the A321LF features 129 economy seats with 36 Economy Plus seats, whereas the A321XLR will feature 118 economy seats with 28 Economy Plus seats. United Airlines currently flies 40 Boeing 757-200s, which operate a mix of premium transcontinental routes and transatlantic services. Delta Air Lines, meanwhile, is planning to take 21 Airbus A321neo aircraft in a premium transcontinental layout, but will not fly the A321XLR.