Efficiency Trends for New Commercial Jet Aircraft, 1960 to 2008
Concerns about aviation’s growing climate impact have revived interest in CO2 emission standards for new aircraft. To date, commercial aviation has been perceived to produce continuous improvements in efficiency by quickly adopting fuel-efficient technologies and designs as a natural response to fuel prices. This paper describes an historical analysis of sales- and activity-weighted fuel efficiency for new jet aircraft from 1960 to 2008 that suggests that fuel costs alone have not produced consistent improvements in aircraft efficiency. Key findings:
- The average fuel efficiency of new passenger aircraft has approximately doubled on both a seat-km (passengers only) and ton- km (passengers + freight) basis since 1960, less than previous estimates.
- New aircraft efficiency has improved substantially in only two of the last five decades, and stagnated in recent years. On average, fuel efficiency has remained flat on a seat-km basis and improved only 0.29% annually on a ton-km basis since 2000.
- Diminished efficiency gains are correlated with historically low fuel prices between 1987 and 2004 and a tripling in the average age of aircraft and engine manufacturer production lines since 1989.
Fuel costs alone have not been sufficient to stimulate increased aircraft efficiency, and improvements in fuel efficiency due to the introduction of new aircraft have decreased over time. These findings suggest that a CO2 standard that applies to newly built aircraft from current production lines, not just to new designs, is most likely to reduce emissions.