Knob under the steering wheel, just pull it
tumbelers in key switch have fell,your local locksmith can replace the switch.
It may be as simple as making sure the vehicle is in "PARK"...some will not allow the key to come out if not in the "P" position..a safety precaution so to speak so one can not lock the keys in the car...also, if the transmission is loose, it may not come completely out of gear so that the key may become stuck in the ignition..
Looking for a Used Thunderbird in your area?
CarGurus has 1,139 nationwide Thunderbird listings starting at $6,995.
Search Ford Thunderbird Questions
Ford Thunderbird Experts