Flying buildable hex-grid

Hi there!

I'm in the middle of making a "flying fortress" type game, but I'm having problems with getting it all to work together. I think my main problem is that I don't understand grids, especially hex-grids. All my attempts so far have been utter failures, as I need to use meshes and not 2D sprites for this one and worse, I need to be able to fly the damned thing as a single transform in vector3.

I want to start from scratch and therefore I hope someone can give me some advice on the following:

What is the best way to create a hex-grid that is able to:

• Behave like a "player" (I have a working health/damage system, and a vehicle controller).

• Be "buildable" at runtime, meaning that the player is supposed to enter "build-mode" and add tiles from the center out by clicking (I have a unit placement system which is supposed to put things on it when built).

I eventually want to make it so that the tiles, when attached to the center "main" tile, randomly create a mesh under the grid making them "grow together". If a part of the grid is separated from the center tile by an inactive tile, that part is destroyed.

I'm also having trouble with my standalone players working in win32, but crashing on Mac OS X / Win64. I'll save that for another question though..

Thanks for reading, and for a great community!