Leeham News and Analysis
There's more to real news than a news release.
Bjorn’s Corner: Faster aircraft development. Part 1.
By Bjorn Fehrm
August 1, 2025, ©. Leeham News: Four years ago I did a series about aircraft development together with Henry Tam and Andrew Telesca. Both worked on the Mitsubishi Spacejet program. You can find the series here.
It was about the arduous task of developing and producing a certified aircraft for the FAA Part 23 standard and its EASA equivalent. The idea was to better describe what’s ahead for the many upstarts that wanted to develop 9-seat and 19-seat alternative propulsion aircraft.
Now we do a series about recent ideas on how the long development times for large airliners can be shortened. New projects talk about cutting development calendar time by one-third or more. Is this realistic?
Figure 1. The A350 development schedule from December 2011. Source: Airbus.
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Bjorn’s Corner: Air Transport’s route to 2050. Part 32. Epilogue.
By Bjorn Fehrm
July 25, 2025, ©. Leeham News: In October last year, we began a series on how air transport is performing against the emission goals for the year 2050.
The ambition to reduce and eventually eliminate greenhouse gas emissions began in earnest 11 years ago, when Airbus flew the Airbus E-Fan at the 2014 Farnborough Air Show (Figure 1).
Figure 1. The Airbus E-fan flying at the 2014 Farnborough Air Show. Source: Wikipedia.
The result of this inspiring flight, which utilized technology that emitted no CO2 or other greenhouse gases (if the batteries were charged with green electricity), was an avalanche of projects from established players as well as upstarts. The optimistic view was that there was a solution to the emissions from airliners.
Bjorn’s Corner: Air Transport’s route to 2050. Part 31, Conclusions.
By Bjorn Fehrm
July 18, 2025, ©. Leeham News: We have done a Corner series on the state of actions to mitigate the global warming impact from Air Transport. Now, we start to summarize what we’ve learned.
During the series, we compiled tables describing the warming effect of air transport in 2024 and a calculation of the effect during 2050. We made two tables, one with the most probable effects, Figure 1, and one where we downplayed the non-CO2 effects to the maximum given in the Lee et al. 2021 study, to a 5% probability, Figure 2.
Figure 1. The effects of Actions 1 to 4 on CO2 and NOx, represented as CO2e emissions during 2050. Source: Leeham Co. Click to enlarge.
Before we summarize by examining the tables, we will discuss the additive effects of CO2 and non-CO2 warming over a given time period, as the different components don’t have the same decay time of their warming effects.
Bjorn’s Corner: Air Transport’s route to 2050. Part 30.
By Bjorn Fehrm
July 11, 2025, ©. Leeham News: We feature a Corner series on the state of actions to mitigate the global warming impact from Air Transport. We try to understand why different developments have been slow.
In the last Corner, we correlated the growth of airliners between 2024 and 2050 and the growth in Greenhouse gas emissions of CO2 and NOx that would result. We also calculated the increase in warming from contrails based on the traffic increase by 2050. The results are in Figure 1.
We also discussed that the warming effects of CO2 are undisputed, whereas the impact of NOx and contrails is less mature in its complicated effects research. The performed research has a lowest and a highest warming probability. We will now do an “acid test” and see what their impact is when we apply their lowest probable effect on global warming.
Figure 1. The effects of Actions 1 to 4 on CO2 and NOx, represented as CO2e emissions by 2050. Source: Leeham Co. Click to enlarge.
Bjorn’s Corner: Air Transport’s route to 2050. Part 29.
By Bjorn Fehrm
July 4, 2025, ©. Leeham News: We feature a Corner series on the state of actions to mitigate the global warming impact from Air Transport. We try to understand why different developments have been slow.
In the last Corner, we wanted to understand the relationship between Greenhouse gas emissions of CO2 and NOx and the effect of global warming from contrails. After some iterations, we arrived at the comparison shown in Figure 1, where we compare different warming effects using CO2 and CO2e (CO2 equivalents, i.e. the same warming effect as CO2).
Figure 1. The Global waring effect of CO2, NOx and warming contrails by 2050 as CO2 and CO2e. Source: Leeham Co. Click to enlarge.
Bjorn’s Corner: Air Transport’s route to 2050. Part 28.
By Bjorn Fehrm
June 27, 2025, ©. Leeham News: We do a Corner series about the state of developments to improve the emission situation for Air Transport. We try to understand why development has been slow.
We have explored various methods to mitigate global warming throughout the series. Over the last few weeks, we have summarized the practical results we can expect from the different alternatives available to reduce global warming in air transport. We looked at the following:
- Alternative, lower-emission propulsion technologies.
- The industry’s typical improvement in fuel consumption over time.
- The improvements that SAF can offer by 2050.
- The different Emission Trading Schemes (ETS) that exist globally.
- And finally, what warming contrail reductions can achieve.
We have summarized what the first four actions can achieve by 2050 and presented the results in a table, Figure 1. Now we add what global warming contrail avoidance can do.
Figure 1. The effects of Actions 1 to 4 on CO2 and NOx counted as CO2e emissions by 2050. Source: Leeham Co.
Bjorn’s Corner: Air Transport’s route to 2050. Part 27.
By Bjorn Fehrm
June 20, 2025, ©. Leeham News: We do a Corner series about the state of developments to improve the emission situation for Air Transport. We try to understand why development has been slow.
We have examined different ways to lower global warming over the course of the series. Over the last weeks, we have summarized what practical results we can expect from the different alternatives we have to reduce global warming from Air Transport. We looked at the following:
- Alternative, lower-emission propulsion technologies.
- The industry’s typical improvement in fuel consumption over time.
- The improvements that SAF can offer by 2050.
- The different Emission Trading Schemes (ETS) that exist globally.
- Finally, what warming contrail reductions can achieve.
Bjorn’s Corner: Air Transport’s route to 2050. Part 26.
By Bjorn Fehrm
June 13, 2025, ©. Leeham News: We do a Corner series about the state of developments to improve the emission situation for Air Transport. We try to understand why development has been slow.
We have examined different ways to lower global warming over the course of the series. Over the last weeks, we have summarized what practical results we can expect from the different alternatives we have to reduce global warming from Air Transport. We looked at the following alternatives:
Bjorn’s Corner: Air Transport’s route to 2050. Part 25.
By Bjorn Fehrm
June 6, 2025, ©. Leeham News: We do a Corner series about the state of developments to improve the emission situation for Air Transport. We try to understand why development has been slow.
We examined alternative, lower-emission propulsion technologies four weeks ago and compared them the following week to the industry’s typical improvement in fuel consumption over time. Then, we examined the improvements that SAF can offer by 2050. Last week, we complemented the picture with the different Emission Trading Schemes (ETS) that exist globally.
Now, we discuss what warming contrail avoidance could achieve in reducing global warming.
Figure 1. A summary of the CO2 and non-CO2 Effective Radiative Forcing (ERF = warming effect) contributions from Air Transport. Source: The report “The contribution of global aviation to anthropogenic climate forcing for 2000-2018” by Lee et al. (2021)
Bjorn’s Corner: Air Transport’s route to 2050. Part 24.
May 30, 2025, ©. Leeham News: We do a Corner series about the state of developments to improve the emission situation for Air Transport. We try to understand why development has been slow.
We examined alternative, lower-emission propulsion technologies three weeks ago and compared them to the industry’s typical improvement in fuel consumption over time the following week. Last week, we examined the improvements that SAF can offer by 2050.
Figure 1. The countries/regions with ETS or Carbon trading systems. Source: Wikipedia.
Before comparing these actions to lower emissions with the Contrail research, we examine the various emission trading schemes currently active worldwide.