The 30-year-old injured man was taken by air ambulance to Selly Oak Hospital in Birmingham, with serious head and internal injuries. A spokesman for Hereford and Worcester Ambulance Service described his condition as critical.
The plane - believed to be a Cessna - crashed into a field near the hamlet of Marston, near Pembridge, about 4.25pm.
The ambulance spokesman said: "Our crews at the scene have spoken to a witness who has reported the plane making a spluttering noise before it came down." He could not confirm reports that the plane caught fire after the crash.