The starting point was a small picture of a motorbike with an extreme fairing based on the drop tank from a Korean-war vintage fighter. That gave me the hull and windscreen. Removed the wheels, added a hatch, ladder, logo, wings from a Jet Provost, model aircraft landing skids, and some Edwardian polar explorers. Fiddled around with it. A lot.
The bastard took me two and a half fricking hours! And I'm still not 100% happy with it, but I think enough is enough, it's reached the point where more fiddling around will make it worse.
Update - here's another that corrects the missing shadows - I'm an idiot...