Ryanair has installed split scimitar winglets on the first of over 400 Boeing 737-800s across its fleet. The winglets similar to those installed on 737 Max jets will improve the aircraft's fuel efficiency by up to 1.5% and reduce Ryanair's annual fuel consumption by 65 million litres, the Irish low-cost carrier says. It adds that the deal with equipment supplier Aviation Partners Boeing is worth $175 million. "As Ryanair grows to carry 225 million passengers by financial year 2026, this initiative will further its target of net-zero by 2050," the airline states.

United Airlines has gained a 10% shareholding in US regional carrier Mesa Airlines, as a "material inducement" related to a capacity-purchase agreement enacted in late December. The US major will get one seat on Mesa's board as part of the deal, which includes a $10 million revolving loan from United, due and payable on 31 January 2024, the carriers say in a 23 January filing to the US Securities and Exchange Commission. Mesa on 27 December entered into an amended capacity-purchase agreement with United, having earlier that month disclosed that it was expanding its existing relationship with United while exiting an arrangement with American Airlines."As a result of ongoing unprofitable operations with American Airlines, driven primarily by higher pilot wages and block-hour utilisation penalties driven by the ongoing industry wide pilot shortage, Mesa initiated and has finalised a consensual wind-down of its American operations," the Phoenix, Arizona-based regional carrier said on 19 December. At the time, Mesa was finalising a five-year agreement with United that would place aircraft into United Express operations and compensate Mesa for the higher costs associated with regional jet flying. The new agreement with United was set to cover "all of Mesa's existing flying at American, and could increase to 38 CRJ900 aircraft, dependent upon the number of [Embraer] E175s that Mesa is operating".

Emirates has operated one of its Boeing 777-powering GE Aerospace GE90 engines with 100% sustainable aviation fuel on the ground, ahead of a planned test flight. The Dubai-based carrier intends to fly a 777-300ER later this week, with one of the twinjet's engines running on full SAF, it says. It adds the ground trial's objective was to demonstrate the GE90's capability of running on "specially blended 100% SAF" without affecting performance and without requiring aircraft modifications or special maintenance procedures. During the ground test, the aircraft's left-hand engine ran on full SAF while the other used standard kerosene, to analyse fuel system performance under each fuel type, compare engine output and ensure seamless operation during the planned test flight. Emirates says the trial at the airline's maintenance centre in Dubai began by operating the 777's Honeywell 331-500 auxiliary power unit with full SAF and then starting-up the two main engines. The left powerplant was put through thrust settings representative of the experimental flight – idle, take-off and climb at "full flight profile durations" and a 15-minute cruise phase. After the simulation ended, the engines were cooled down and fuels were isolated in separate tanks to maintain segregation. At Dubai airshow 2021, Emirates, GE Aerospace and Boeing had signed a memorandum to develop a programme to trial 100% SAF on a 777-300ER in flight, the airline notes.