Douglas mailplanes
| M-1/M-2/M-3/M-4 | |
|---|---|
| General information | |
| Type | Single-seat mailplanes |
| Manufacturer | Douglas Aircraft |
| Primary users | United States Post Office |
| Number built | 57 |
| History | |
| Introduction date | 1926 |
| First flight | 1925 |
The Douglas mailplanes are a family of 1920s American single-seat mail planes designed and built by the Douglas Aircraft Company. The aircraft were used to run the main routes of the United States Air Mail service until the introduction of three-engined aircraft in 1928.