> Where were the tanks? The airplanes? The warships?
I don't know about the tanks, but the airplanes and warships were all over the place - they just weren't property of the German military. Germany was building subs in the Netherlands, and aircraft in Russia - they got around the treaty by offshoring production and selling to other nations, allowing them to refine their designs and build their industry. They did a similar thing with the officer corps - they just changed their titles, but continued perfecting and growing their training program. Conscription is pretty much the last thing to happen, if you want to watch for trouble - watch the officer training program. All that was going on in the 1920s btw.
All this might sound like Monday morning quarterbacking, but the pattern is repeated throughout history. Watch Turkey. If they rebuild their officer corps before their economy totally collapses, they'll try to annex northern Syria and northern Iraq. They've started developing domestic production of weapon systems, dropped very strong hints that they aren't interested in remaining a NATO partner, and they have a madman as chief executive - enthusiastically put their by nationalists.