[mailchimp_signup][/mailchimp_signup]The International Council on Clean Transportation (ICCT) has examined emissions from more than 25,000 planes produced between 1960 and 2008. It shows improvements in fuel efficiency for the first three decades, but virtually no improvements in the last 20 years when there have been few new aircraft designs. The International Civil Aviation Association recently proposed a CO2 standard for new aircraft designs, but rejected suggestions that designs currently in production should be subjected to a maximum level of emissions. But Daniel Rutherford, a co-author of the ICCT’s report, says this will mean improvements will happen far too slowly. 'Conventional wisdom holds that fuel prices drive constant improvements in new aircraft efficiency,' he said, 'but our analysis suggests efficiency improvements only tend to come with the introduction of new designs, which are much less common today.' As a result, the ICCT fears that without a CO2 standard covering aircraft from both new and existing lines, airframe manufacturers could have a financial incentive to delay the introduction of more efficient engines in favour of older, unregulated models. In a separate development, the head of the low-fares airline EasyJet has accused airframe makers of delaying delivery of cleaner, more fuel-efficient planes. 'They are in no hurry to bring them out,' Andy Harrison told a news conference, 'because the cash flow they have from the Boeing 737 and Airbus 320 narrow-bodied planes is what they are interested in, and they want to keep that going.' Responding to the accusation, a spokesperson for Airbus told Air & Business Travel News that technology to make planes quieter was available, as was technology to combat emissions, but that combined technology tackling both noise and emissions concerns was still in development and 'would not be available for around another 10 years.'