A 22-year-old woman was airlifted to hospital after her car overturned near junction 1 of the A14 on Sunday afternoon.
Warwickshire and Northamptonshire Air Ambulance (WNAA) were called out at the request of East Midlands Ambulance Service and landed at the scene at about 1.18pm.
The patient had been rescued from the vehicle by firefighters and was treated at the scene by ambulance crews.
Sam Conway, spokesman for WNAA, said: “Our crew assisted with immobilising the patient, who sustained back injuries in the incident.
“She was then airlifted to University Hospitals Coventry and Warwickshire for further treatment. Her current condition is unknown.”
So far in 2014, WNAA have been called out to more incidents in Northamptonshire than any other county.