A small twin-engine airplane crashed into a cornfield on Harrington Road, east of the bypass in the town of Waupaca.
A 911 caller reported at 11:20 p.m. Friday that the crash occurred near his home.
The 47-year-old pilot, Andrei Biesinger, age 47 of Oshkosh, was the only occupant of the plane.
Waupaca firefighters extricated him from the plane.
He was transported by ambulance to Waupaca Airport and then airlifted to Theda Clark Medical Center in Neenah with severe injuries.
Waupaca County deputies, Waupaca police and state patrol officers were at the scene.
The Federal Aviation Administration is investigating the crash.