Man critical after fiery car crash in SA

A man is in a critical condition after his car tree hit a tree and burst into flames in Adelaide's north.

The collision happened just after 7pm on Thursday when the man's Holden Astra collided with a BMW on Womma Road, Penfield, smashed into a tree and caught fire.

Witnesses pulled the injured driver from the vehicle. The 23-year-old man was treated at the scene before being taken to Royal Adelaide Hospital. The driver of the BMW wasn't injured.

Womma Road was closed for several hours for police crash investigation work before being reopened just after 10pm.

In a separate incident on Thursday, a 34-year-old motorcyclist was airlifted to hospital following a collision with a car near Loxton.

Police say the crash happened on Bookpurnong Road near Loxton High School just after 3pm.

The a 34-year-old rider was taken to the Berri Hospital, before being airlifted to the Royal Adelaide Hospital where he remains in a critical condition. The driver of the car was uninjured in the crash.

Major Crash Officers attended the scene before the road was reopened just before 11pm.