Have you considered Seattle? You can visit the Museum of Flight and take a tour in the Boeing factory.
As I mentioned above, I am with parents, so actually not too aviation-based stuff... that is why I canceled SEA-TAC already, as this would be a main destination
Currently we go through Chicago's website offering a far not as dark opinion and look at the city. Surely they want to get visitors into the town, but I think that it will be somewhere in the middle.
Another thing is, that (as a lilius pointed out on skype) I am (kindof) supposed to see all major US-cities, so I will be over the pond every once in a while
The point of the trekking is what we found unnecessary to get to the USA to, as we have better place to do it in here in Germany...
Thanks so far -we are about to book, I will update