Have noticed a few times now that carrier has been sailing on land(ie no water) thought I'd just see what would happen if I stopped tank in front of it. Ship carries tank along and does 90sec countdown resetting as it goes over bumps. Doesn't seem in spirit of game, interesting thou.

Well you are asking for trouble. It is bad enough that the game has a multitude of vampires, wolfmen, ghosts and as far as I have seen one zombie. Landing where the water used to or should be is giving an invite to the Land Sharks to take over your tank or plane. Seeing that sharks do not have opposable thumbs they may not begin to be able to use the controls of these craft right away but it will not take long before they understand the technology. Lets not "poke the bear" or in this case the "shark" by giving them the chance.