Aluminum-lithium alloys have been developed primarily to reduce the weight of aircraft and aerospace structures. This Article commences with a discussion on the physical metallurgy and development of aluminum-lithium alloys. It focuses on major commercial aluminum-lithium alloys, including alloy 2090, alloy 2091, alloy 8090, alloy CP276, and Weldalite 049. The Article also lists the chemical compositions, physical properties, fabrication characteristics, corrosion performance, and general applications of these alloys. A comparison of alloy properties is represented graphically.