LMI Aerospace, Inc. provides structural assemblies, kits and components, and design engineering services to the aerospace and defense markets in the United States. Its Aerostructures segment offers machined and formed close-tolerance aluminum, specialty alloy and composite components, and assemblies. It provides edge assemblies, wing slats and flap skins, ailerons, verticals, and vanes; winglet edges and modification kits; fuselage and wing skins; helicopter cabin and aft section components and assemblies; wing panels; tail cone assemblies; thrust reversers and engine nacelles/cowlings; door components, assemblies, and floor beams; cockpit window frames and landing light lens assemblies; and cockpit crew floor and bulkhead structure assemblies. This segment also offers wheel well and electronic rack assemblies; interior components; structural sheet metal, machined, milled, and extruded components; housings and assemblies for gun turrets; auxiliary power unit components; fans and heat exchangers; and assemblies and components for rail yard switching equipment. Its Engineering Services segment provides engineering design, analysis, repair, certification, and program management services. This segment offers wing/wingbox, fixed and moveable trailing edges, fuselage, empennage, and tail cone design; winglet/wing mod design; nacelle, engine cowl, and thrust reverser design; weight improvement engineering; helicopter fuselage, cockpit, cabin frames, skins, longerons, and beams; aircraft modification engineering; systems design and integration; tool design and fabrication; after-market engineering and support; aviation training system; and aviation maintenance engineering services. The company was founded in 1948 and is headquartered in St. Charles, Missouri. As of June 27, 2017, LMI Aerospace, Inc. operates as a subsidiary of Sonaca SA.