Boeing Co., Lockheed Martin Corp., BAE Systems and Raytheon Co. officially announced Tuesday that they plan to launch a joint Internet trading exchange for the global aerospace and defense industry. Commerce One is slated to be the technology partner, and Microsoft Windows 2000 will be the base software for the site. The exchange, which is expected to launch mid-year, is currently recruiting additional manufacturers and suppliers. The global aerospace and defense industry has commercial and military sales of more than $400 billion. The four lead participants in the venture do business worldwide with more than 37,000 suppliers, hundreds of airlines and national governments, all of which will be invited to join the Web-based marketplace. Together, the four companies founding the independent site procure about $70 billion annually from suppliers.