| XP-4 | |
|---|---|
 Boeing XP-4 during trials | |
| General information | |
| Type | Fighter |
| National origin | United States |
| Manufacturer | Boeing |
| Number built | 1 |
| History | |
| First flight | 1927[1] |
| Developed from | Boeing Model 15 |
The Boeing XP-4 was a prototype American biplane fighter of the 1920s. It was grounded permanently after just 4.5 hours of flight testing.[1]