I tested every vehicle I have avalible. The Captains are vastly incompatible with most vehicles but not all. They can fit in most turret sections very comfortably, also the Banshees reasonably well. Wile jutting out of the open top vehicles they can indeed sit in them, poorly. With some bending back they can fit inside the Kodiak siege cannon, hilariously the Grimmlion/Elephant V2 and the CoD Humvee. They can not fit in pretty much any closed roof vehicles. This includes all Halo and CoD vehicles with the exseption of the ones listed above. Also... ya... no aircraft sept Banshees... too bulky. They are not able to fit in any of the Halo Cyclops. They of course can fit in all large spaces inside the transport vehicle and inside the enemy destiny sets. (Caball Harvestor and Caball Golioth Tank)