I was expecting a lot of difficulty based on some of the other reviews, however, I was able to put this model together without any problems. If you take your time and are careful removing the pieces, you should be fine. I did not break one single part. They are attached with just enough wood left to hold them in place and came off cleanly for me. A couple of hints. Work the pieces from both the top and bottom until it loosens, then you'll see the best way for it to pop out. For those that ended up with a non functioning model, make sure everything moves freely. This means that it must rotate several times when you flick it with your finger. Mine did not work the first time even though it seemed to move freely. I thought freely meant I could rotate it with my fingers. I found the two large back wheels were binding a bit and squeezed them together so there was no friction at the two ends. After that it moved very freely and would rotate 6-8 times on a single flick of my finger. Once that was fixed I gave it a flick to start it and simply blew into the opening and it ran as fast and long as my breath would hold out. Though I didn't have a balloon, I have no question that it would work fine with that as well. All in all I thought this was a very well made model and was a lot of fun to put together.
