A Norlane man's been charged over what police suspect may have been a car surfing accident in Geelong's northern suburbs.

A 30-year-old man fell from the back of a moving car at the corner of Iona St and Sparks Rd around four yesterday afternoon.

He was flown to hospital in Melbourne suffering serious head injuries.

Police say a 30-year-old man has been bailed to face court next month on charges of conduct endangering life and recklessly causing serious injury.

A 38-year-old woman in the car at the time was interviewed but has since been released while police continue their inquiries.