Kelly Young in New Scientist:
On 14 June 2005, Japan and France signed an agreement to develop jointly a new supersonic commercial jet. The three-year research plan includes developing lightweight composite materials.
The proposed aircraft could hold 300 passengers – three times that of Concorde – and would aim to make the New York to Tokyo journey in just 6 hours. It could be in business as early as 2015.
Japan also aims to cut the noise created by the jet’s sonic booms and reduce the nitrogen oxide emissions from the flights.
NASA is also funding research into designing supersonic aircraft with a smaller sonic boom and less pollution in its Sonic Boom Mitigation Project, based at Langley Research Center in Hampton, Virginia, US. In May 2005, the agency awarded four industry teams $1 million each for a five-month study, says Kathy Barnstorff, a Langley spokesperson.
More here.