Farmer Paul Morriss, who owns the paddock where the two badly smashed vehicles landed after crashing through a fence, also heard the impact and telephoned emergency services before making his way to the crash scene with a fire extinguisher.
Eketahuna fire chief Max Mayer said a crew using the jaws of life cutting equipment had to take the roof of Mrs Rutherford's vehicle off, and slice through the side panels to free her.
Mr Mayer said he believed the trapped woman, who had been travelling along South Road No 2, had remained conscious throughout.
Once she was extracted from the wrecked car Mrs Rutherford was stabilised by St John ambulance staff before being flown to hospital.
A police serious crash unit was on the scene yesterday and is investigating the circumstances of the crash.