Tried & tested quick release car headrest vehicle mount with adjustable holder suitable for the Apple iPad.
One of favorite car mounts, combines an adjustable cradle with a secure vehicle headrest mount.

360º swivel & tilt. Adjusts easily for smaller or taller passengers. Locking ring holds position.

Button release ratchet jaw accommodates your tablet device and allows room so you can keep it in a protective case if you wish.
Slide along support feet keep ports free.

Simply insert your tablet and secure by pushing the support arms together.
Foam padding supports the device.

Secure quick release clips are suitable for almost any headrest posts. Very easy to fit & remove.

This cradle is suitable for:
Apple iPad mini, iPad, iPad 2, iPad 3
Samsung Galaxy Tab, Tab 7.7, 8.9" Tab 2 GT-P5110 10.1", Galaxy Note 10.1
Asus Google Nexus 7", Transformer,
HTC Flyer
Blackberry Playbook
HP Touchpad
Lenovo IdeaPad
CnM 9"
Toshiba Thrive
Prestigio 9.7 & 7"
Xoom & Xoom 2
Amazon Kindle Fire HD
Along with many others.

Video example of the headrest mount