The manufacture, assembly, re-building, alteration and repair of aeroplanes; gliders, aircraft parts such as engines, propellers, pontoons and under-carriages; space vehicles and specialized parts; and hovercraft and specialized parts. The manufacture of aeronautical electrical equipment is classified in the appropriate group of major group 383 (Manufacture of electrical machinery, apparatus, appliances and supplies); the production of aeronautical measuring instruments is classified in group 3851 (Manufacture of professional and scientific equipment and measuring and controlling instruments); the fabrication and assembly of missiles and rockets is classified in group 3829 (Manufacture of machinery and equipment except electrical not elsewhere classified).