Leeham News and Analysis
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Bjorn’s Corner: Faster aircraft development. Part 28. Development times.
By Bjorn Fehrm and Henry Tam
February 20, 2026, ©. Leeham News: We have, since August 2025, gone through an FAA CFR 14 Part 25 development project of an airliner in the 200-seat class. The aim was to identify the activities required for such a project and the regulatory actions needed to achieve Type Certification (TC) and Production Certification (OC) for the aircraft.
The program followed the time plan in Figure 1, which indicated that it would take about seven years from the start of conceptual design to deliver the first aircraft and enter service (EIS). At each phase, we assessed whether modern support techniques, such as AI, could help with development and certification and whether they would accelerate the program plan.
Figure 1. A typical Program Plan for a smooth-running Part 25 airliner development. Source: Leeham Co.
We now summarize the findings and incorporate additional modern support, such as Digital Twin support, to assess the overall impact of today’s technologies on the program plan timeline in Figure 1. Read more
Bjorn’s Corner: Faster aircraft development. Part 27. Where Speed-Up gets Tough.
By Bjorn Fehrm and Henry Tam.
February 13, 2026, ©. Leeham News: We are summarizing how modern tools, processes, and AI can help reduce the time required to develop a clean-sheet 200-seat replacement for the Airbus A321neo and the Boeing 737 MAX 10.
We discussed some ideas in the last article on how current AI can support development. We could see it helping reduce the time spent on templating documents and on designing and verifying simple parts, such as mounting brackets for pipes and cables.
To address the more challenging parts where AI struggles to assist, we need to understand why development programs now take longer than in the past and what can be done to shorten the timeline.
Outlook 2026: The state of the major eVTOL projects
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By Bjorn Fehrm
February 9, 2026, © Leeham News: The eVTOL market saw a sobering 2025 after two of its high flyers, Lilium and Volocopter, both ceased operations in 2024. The remains of Volocopter were bought by Diamond Aircraft, which now markets a stripped-down VoloCity as a Light Sports eVTOL.
Further players ceased in 2025, with Hyundai’s Supernal halting further development, as did Airbus with its CityAirbus. Textron halted Nexus development, then shuttered the division, and Overair ceased operations after Hanwa stopped investing.
We have one VTOL that received local Chinese Type Certification in 2023, and one in 2024. EHang got the Type Certificate in 2023, Production Certificate in 2024, and Air Operator Certificate (AOC) in 2025. The drone multicopter looking Ehang EH216-S (Figure 1) was cleared to operate tourist flights in China. The other Chinese project was AutoFlight’s Prosperity five-seater, which achieved Chinese Type Certification in 2024.
Figure 1. The only certified eVTOL, the EHang EH216-S. Source: EHang.
The almost euphoric enthusiasm over eVTOLs that existed before COVID, where car manufacturers got involved as this could be the thing that took over personal transport for crowded cities, has now calmed down, as the operational use of the current generation of eVTOLs is 10 to 15-minute missions in fair weather, replacing helicopter services from the airport to the city centre.
The original story was different as early developers like Joby Aviation painted with a broad brush. There were statements about 150nm trips, 200 kts speeds, and unbeatable economics, with batteries that lasted 10,000 flights. What investors and pundits didn’t understand was that these were unrelated statements about physical limits: there was no AND between them.
Bjorn’s Corner: Faster aircraft development. Part 26. AI speeds up processes.
By Bjorn Fehrm and Henry Tam
February 6, 2026, ©. Leeham News: We have completed a detailed, step-by-step analysis of the certification requirements a Part 25 Air Transport airliner in the 200-seat segment must meet.
In our series, we have seen work that could benefit from an AI agent, and other work where we conclude it will be difficult.
We begin this week by outlining areas where we expect AI to reduce the number of work hours required to complete a task. We will attribute these AI-driven work-hour reductions to the appropriate areas of the aircraft Program Plan in Figure 1.
Figure 1. A generic new Part 25 airliner development plan. Source: Leeham Co. Click to see better.
Outlook 2026: The airliner projects that promise new technology and lower emissions
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By Bjorn Fehrm
February 5, 2026, © Leeham News: We survey new entrants that deviate from the classical gas-turbine tube-and-wing airframe concept and offer airliners the promise of lower emissions and, hopefully, lower costs.
We will do this by starting with those closest to certification and delivery, then tapering off to those who currently fly on PowerPoint.
If we didn’t apply this filter to what we consider real projects, we would describe over 50 entries, with additional ones announced with airline orders every month over the last few years. Few of these have progressed beyond plans, which is why we focus on those that have.
Overall, it’s amazing that 11 years after the Airbus E-fan battery-electric aircraft flew at the Farnborough Air Show in 2014, we still do not have a single certified alternative-propulsion passenger aircraft. We have one light-sport two-seat trainer, the Pipistrel Electro Velis, but nothing else.
Figure 1. The Airbus E-Fan at the Paris Air Show in 2015. Source: Wikipedia.
Rolls-Royce 2026 Outlook: It’s back in large engines; can it get back into the Single Aisle as well?
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By Bjorn Fehrm
January 29, 2026, © Leeham News: Rolls-Royce has posted a string of increasing profits over the last few years after a tough period that 
started in 2017, when its Trent 1000 engines on ANA’s Boeing 787s developed a turbine-corrosion problem, cutting time on wing to a fraction of what it should be. These turbine problems escalated into a global issue, affecting all Trent 1000-equipped 787s.
The Trent 1000 on Boeing’s 787 has since experienced a series of problems, beginning with the need to replace turbine blades, followed by compressor vibration that required replacing blades on the intermediate compressor. Engines must be removed from the wing to remove the turbine and compressor blades during engine overhaul, resulting in Rolls-Royce Trent-equipped 787s being grounded for periods.
The result has been a dwindling market share for the 787, with the competing engine OEM, GE, now claiming an 78% market share for its GEnx-1B engine, and charges to the business for the cost to fix the problems for the airlines.
The drama surrounding the 787 was not expected. The Rolls-Royce RB211-535 had been the best engine on the Boeing 757 (versus Pratt & Whitney’s PW2040), and on the Airbus A330, the Trent 700 has a dominant market share versus GE’s CF6 and Pratt & Whitney’s PW4000, as it offers solid performance and maturity.
To add to injury, a former management had decided that the Single Aisle market was too small a fish for Rolls-Royce and exited the cooperation with Pratt & Whitney for the A320/A321 V2500 in 2011. The aftermarket income from spares for the V2500 began to decline as the Trent 1000 kept 787s on the ground and COVID-19 hit. When COVID hit in 2020, Rolls-Royce struggled with losses because of these engine problems and strategic mistakes.
Pratt & Whitney builds for the future while wrestling with the present
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By Bjorn Fehrm and Charlotte Bailey
January 26, 2026, © Leeham News: Pratt & Whitney (PW) bet big on the geared turbofan to take it back to a sizeable position in the market’s largest airliner segment, the Single-Aisle. It spent more than 20 years to develop the fan gearbox, including functional demonstrator engines that flew on Airbus test aircraft to prove the technology.
The effort was a success; the gearbox in the Pratt & Whitney range of Geared TurboFans, GTFs, has worked perfectly. It achieved what was promised, a low fuel consumption, and has been rock-solid in its function.
Yet PW’s GTFs have had a range of problems since their introduction in 2016. Bent main shafts, combustors that burn through, bearings that fail. And on top, a huge call-back of engines, as a contaminated power metal process has produced compressor and turbine discs that risk failing before their on-engine life expires. The situation has caused over 600 Airbus A320 and A321neos with GTF engines to be grounded for engine replacements, if and when replacement discs are available.
The issues, stemming from the “business as usual” parts of the GTF, have led to write-offs of billions of dollars for PW’s mother RTX and to lost market share to the competing CFM LEAP engine on the Airbus A320/321neo series. But while this clouds the business of yesterday and today, Pratt & Whitney still has the clout to invest in the future. Being part of one of the World’s largest Defence and Aerospace Companies is an important part of the answer.
Figure 1. The Maeve MJ500 with the revolutionary Pratt & Whitney Canada Constant Volume Open Fan engine. Source: Maeve. Read more
Bjorn’s Corner: Faster aircraft development. Part 24. Post certification, Sustainment phase.
By Bjorn Fehrm and Henry Tam.
January 23, 2026, ©. Leeham News: We do a series about ideas on how the long development times for large airliners can be shortened. New projects talk about cutting development time and reaching certification and production faster than previous projects.
The series will discuss the typical development cycles for an FAA Part 25 aircraft, called a transport category aircraft, and what different ideas there are to reduce the development times.
We will use the Gantt plan in Figure 1 as a base for our discussions. We have looked at the preparation work around entry into service; now we talk about post-certification work and the support of the new airliner generating revenue flights for the airline customer.
Figure 1. A generic new Part 25 airliner development plan. Source: Leeham Co. Click to see better.
** Special thanks to Andrew Telesca for helping with this article **
Bjorn’s Corner: Faster aircraft development. Part 23. Preparing for Entry Into Service.
By Bjorn Fehrm and Henry Tam
January 16, 2026, ©. Leeham News: We do a series about ideas on how the long development times for large airliners can be shortened. New projects talk about cutting development time and reaching certification and production faster than previous projects.
The series will discuss the typical development cycles for an FAA Part 25 aircraft, called a transport category aircraft, and what different ideas there are to reduce the development times.
We will use the Gantt plan in Figure 1 as a base for our discussions. We have looked at the production preparations and the challenges of the serial production phase. Now we look a the preparation work around entry into service for our new airliner.
Figure 1. A generic new Part 25 airliner development plan. Source: Leeham Co. Click to see better.
Bjorn’s Corner: Faster aircraft development. Part 22. Serial Production.
By Bjorn Fehrm and Henry Tam.
January 9, 2026, ©. Leeham News: We do a series about ideas on how the long development times for large airliners can be shortened. New projects talk about cutting development time and reaching certification and production faster than previous projects.
The series will discuss the typical development cycles for an FAA Part 25 aircraft, called a transport category aircraft, and what different ideas there are to reduce the development times.
We will use the Gantt plan in Figure 1 as a base for our discussions. We have completed flight testing of the flight test aircraft and obtained a design Type Certificate (TC). We now examine the production preparations and the serial production phase.
Figure 1. A generic new Part 25 airliner development plan. Source: Leeham Co. Click to see better.