I think that he used Poser for the pics with people. This is a great option, but does have a bit of a learning curve, mostly to pose. I think it used fairly extensively in animation as well. More importantly, the bodies need props like uniforms, etc. I looked into this a few years ago, and this is what discouraged me the most from doing anything. There are a few free props around the web, but not enough many to fill all the needs for various peoples, etc. Thus, one needs to make them with a 3D program. But, not only that, in order to use them as a prop on a body, there is an additional step to make them conform to the body. I never got that far, and gave up.
For the vehicles, I think he used a fairly simplistic 3D model program and then imported and rendered them in Poser.
For the aircraft I made, I used Blender, which is a free, but rather sophisticated 3D model program with a beautiful render engine. It has a steep learning curve as well. But, it is not a great choice, near as I can tell for "animating" people.