United Airlines has converted a portion of its Boeing Max 10 orders scheduled for delivery from 2025 through 2027 to Max 9s, and may convert additional Max 10s to Max 8 and 9 aircraft. Additionally, the US major says it has signed letters of intent with two lessors to receive 35 new Airbus A321neos with CFM engines in 2026 and 2027. The Max order conversions and A321neo leasing deals disclosed on 16 April follow long-term manufacturing slowdowns at Boeing and Airbus, delayed certification of the Max 10 and the Alaska Airlines Max 9 door-plug blowout event on 5 January, which forced United to temporarily ground its 79 Max 9s. At the end of 2023, United had contractual commitments with manufacturers for 183 narrowbody deliveries this year. The Chicago-based carrier at the beginning of 2024 nevertheless expected manufacturing delays would result in 101 narrowbody deliveries. A further dimming of expectations was to come. "Following the 737 Max 9 grounding and the FAA's announced significant production capacity constraints on Boeing, the company now anticipates 61 narrowbody aircraft and five widebody aircraft to be delivered in 2024," United said on 16 April. United has on order 346 Max jets, 150 787s, 172 A321neos and 45 A350s. "We've adjusted our fleet plan to better reflect the reality of what the manufacturers are able to deliver," United chief executive Scott Kirby states. "We'll use those planes to capitalise on an opportunity that only United has: profitably grow our mid-continent hubs and expand our highly profitable international network from our best in the industry coastal hubs."
United notes that the grounding of its Max 9 fleet earlier in 2024 had a "$200 million impact" on its first-quarter financial results, "without which the company would have reported a quarterly profit". The carrier in the first quarter of 2024 made a net loss of $124 million, narrowing its net loss of $194 million in the same period last year. It made an operating profit of $99 million, reversing its operating loss of $43 million in the first quarter of 2023. United generated $12.5 billion in total operating revenue in the first quarter, up 10% year on year. Total operating expenses grew 8%, to $12.4 billion. The carrier ended the first quarter with liquidity of $16.9 billion, and total debt and finance lease obligations of $27.2 billion.

The EU's aviation regulator and its Chilean counterpart intend to increase their co-operation and work toward common safety and environmental standards. Under a working arrangement signed during the recent FIDAE air show in Santiago, the European Union Aviation Safety Agency and Chile's Direccion General de Aeronautica Civil say they have agreed to "facilitate and accomplish the DGAC acceptance or validation of certificates issued by EASA" for aerospace products, parts and appliances. They add that the accord covers co-operation on continuing airworthiness of EASA-approved equipment that has been validated/accepted by the DGAC and on export documentation where such products are being delivered to Chile. Another objective is to "strengthen the regular exchange between the DGAC and EASA with regards to the institutional and regulatory harmonisation and technical requirements in the field of aviation safety, interdependencies between safety and security and environmental protection". The DGAC's aim is "to go through a harmonisation process with the International Civil Aviation Organization (ICAO) standards and converge when appropriate with the EU system and EU aviation safety rules and EASA measures. Both sides recognise the continuous trend towards multinational design, production and operation of civil aeronautical products and have considered the need to reduce the economic burden imposed on the aviation industry and protectionist barriers, together with the demand to further promote industrial and scientific co-operation." The working arrangement covers "all regulatory aspects in the domains of civil aviation safety", EASA and the DGAC note.

Air New Zealand will buy nine million litres of Sustainable Aviation Fuel from Neste that will be supplied for blending and uploading at Los Angeles between April and November. The SAF will be produced at Neste's Singapore refinery, and the deal marks the largest purchase of SAF from Neste by any airline outside North America and Europe for delivery before the end of 2024, the carrier says. "Decarbonising Air New Zealand's operations is essential for the airline's long-term ability to connect New Zealanders to the world, as well as support the country's trade and tourism sectors, and SAF is a key enabler of this", Air New Zealand's chair Therese Walsh says. "While the SAF supply is small compared with the airline's overall fuel use, it is nine times the size of Air New Zealand's first shipment of SAF from Neste in 2022 and demonstrates growing co-operation between two like-minded organisations to advance the supply and use of SAF." The Neste deal comes less than a month after Air New Zealand issued an "opportunity statement" seeking global partnerships to supply SAF, which it aims to make up around 20% of its fuel uptake by 2030.