The Macchi M.39 was a racing seaplane designed and built by the Italian aircraft company Aeronautica Macchi in 1925–26. The M.39 was designed by Mario Castoldi to represent Italy in the 1926 Schneider Trophy competition, and was the first low-wing monoplane that he designed for Macchi. It was a single-seat twin-float seaplane of mixed (metal and wooden) construction. Macchi built two versions of the M.39, a trainer version and a racer. The trainer version had an increased wingspan of 10.23 metres (33ft 7in) -compared to the 9.26m (30ft 4.5in) of the racers. The first M.39, a trainer with serial number MM.72, was built in only a few months. It was soon followed by the second trainer (MM.73), the three racers (MM.74, MM.75, and MM.76), and the static-test airframe.
| Country of origin | Italy |
| Performance | Maximum speed: 439.44 km/h (273.06 mph, 237.28 kn) |
| Dimension | Length: 7.77 m (25 ft 6 in) including floats |
| 6.73 m (22.1 ft) fuselage length | |
| Height: 2.97 m (9 ft 9 in) | |
| Empty weight: 1,257 kg (2,771 lb) | |
| Gross weight: 1,572 kg (3,466 lb) | |
