Farnborough, England--The Boeing Co., Raytheon Co., Lockheed Martin Corp. and BAE Systems announced Tuesday at the Farnborough International 2000 air show that they have signed a definitive agreement to create an e-marketplace for the global aerospace industry. Called Exostar, the e-marketplace is expected to be conducting transactions by the end of September. The site is currently operating at www.exostar.com. The headquarters for the exchange will be in the Washington area.