The rider was involved in a collision with a car on the B743 close to the Whitlets Roundabout near Prestwick, Ayrshire, around midday today.
The Scottish Ambulance Service said a trauma team from the Southern General travelled to the scene of the incident by air to treat the man, believe to be in his forties.
He was then flown to hospital in Glasgow. He is believed to have suffered serious injuries.
A spokeswoman for Police Scotland said: “A car and motorbike were involved in a collision on the B743 at around 12.15pm today. The air ambulance was called in and one casualty has been airlifted to hospital.
“Police are still at the scene of the incident.”