US major United Airlines is on 1 December operating a fully occupied flight from Chicago O'Hare to Washington National with one engine using 100% sustainable aviation fuel. The flight, which United describes as "unprecedented", is being conducted with a new Boeing 737 Max 8. It will use 500 gallons of SAF in one engine and the same amount of conventional jet fuel in the other. Airlines are permitted to use a maximum of 50% SAF on board, United says. The Star Alliance carrier intends to demonstrate that there are no operational differences between the two kinds of fuel. Boeing, CFM International, Marathon subsidiary Virent and SAF producer World Energy are United's partners in the demonstration flight. The airline's chief executive Scott Kirby states: "Today's SAF flight is not only a significant milestone for efforts to decarbonise our industry, but when combined with the surge in commitments to produce and purchase alternative fuels, we're demonstrating the scalable and impactful way companies can join together and play a role in addressing the biggest challenge of our lifetimes." Ihssane Mounir, Boeing's senior vice-president of sales and marketing, adds: "As an industry, we are committed to addressing climate change, and sustainable aviation fuels are the most measurable solution to reduce aviation carbon emissions in the coming decades." United declares itself the "world leader" in the development of SAF, asserting that it has agreements to purchase "nearly twice as much SAF as the known agreements of all other global airlines combined". The carrier has meanwhile disclosed the recruitment of 12 additional companies to its Eco-Skies Alliance, launched in April to accelerate SAF development and use. More than 30 companies now participate in the alliance, which United says has so far contributed toward the purchase of more than 7 million gallons of SAF in 2021.

Ethiopian Airlines has finalised preparations for the December launch of the new Zambia Airways, in a joint venture with the Zambian Industrial Development Corporation (IDC). The new airline, Ethiopian says, will launch its initial domestic flight from Lusaka to Ndola on 1 December and it will operate to Ndola and Livingstone at a frequency of six and five times a week, respectively. Other domestic routes to Mfuwe and Solwezi will follow, it says, with regional destinations, Johannesburg and Harare, to be added to its network within the first quarter of 2022. Ethiopian has a 45% stake in the joint venture while IDC retains 55%. The shareholders have contributed $30 million in capital towards the establishment of the airline. Ethiopian Airlines’ group chief executive Tewolde GebreMariam states: “The strategic equity partnership in the launching of Zambia’s national carrier is part of our vision 2025 multiple hub strategy in Africa. “Ethiopian is committed to its growth plan in collaboration with African carriers and the new Zambia Airways will serve as a strong hub in Central and Southern Africa availing domestic, regional and eventually international air connectivity for passengers and cargo to the major destinations in the Middle East, Europe and Asia, which will enhance the socioeconomic integration and tourism industry in Zambia and the region.”

Three US lawmakers have written to Federal Aviation Administration chief Steve Dickson demanding more detailed answers to questions on how Boeing is being held accountable for past "transgressions" related to the 737 Max. In a 29 November letter to Dickson, the US House Committee on Transportation and Infrastructure's chair Peter DeFazio, aviation subcommittee chair Rick Larsen and subcommittee member Greg Stanton call on the FAA administrator to provide "more complete responses" to questions raised during a hearing he attended last month. Specifically, the letter's authors want to know what the FAA has done to hold to account Boeing employees responsible for an "apparent violation" of the 737 Max's approved type design, and for the manufacturer's "internal plan" to downplay the significance of the aircraft's Manoeuvring Characteristics Augmentation System (MCAS) to regulators. Boeing equipped the 737 Max with MCAS to counter the aircraft's tendency, in certain situations, to pitch nose-up. The system, acting in response to erroneous angle-of-attack (AOA) data, was implicated in two fatal crashes involving Max 8s operated by Lion Air and Ethiopian Airlines. "We are deeply troubled by the absence of rigorous accountability for Boeing's past transgressions related to the 737 Max and the FAA's failure to hold those who violated the public's trust accountable," write the congressmen in the letter. They accuse Boeing of failing to notify regulators about a non-functioning AOA Disagree alert on more than 80% of Max aircraft until after the Lion Air crash in October 2018. To date, they add, "we are unaware of any actions the FAA has taken to hold Boeing accountable for violating the approved type design of the 737 Max, knowingly continuing to manufacture the aircraft regardless of this known defect, and failing to notify your agency – or 737 Max customers – of this non-functioning component on the aircraft until after the Lion Air crash". The second issue highlighted in the letter concerns an "explicit plan" by Boeing to downplay the significance of MCAS. "We would like to know what, if any, actions FAA has taken to evaluate and investigate the efforts by Boeing to downplay MCAS, particularly to US and foreign regulators," write the congressmen. "We are interested in any actions by the FAA to hold individuals accountable for their actions." DeFazio, Larsen and Stanton have requested a response to their letter from the FAA by 13 December.