Shen likes walking - or limos! He enjoys limos, or any other sort of four-wheeled vehicle. Planes are nice two. Motorcycles...

Motorcycles have him clinging to Celty for dear life. Not that he doesn't trust her - far from it! But trust doesn't exactly alter how radically different this is from anything he's used to.

(Even if there's that stupid deja vu sense he's continually trying to repress.)