Boy vs. Girls--Legos

Before I had kids, I thought that each child was an individual, and didn't believe much in gender stereotypes in children. Little boys ran and jumped a lot because that's the kind of games they were taught. Little girls played with dolls because that was the kind of toys they were given. I thought that if all kids, regardless of gender, were exposed to the same things, they would have the same tendencies. Then I spent some time in the real world of kids and figured out that I was wrong. Possibly there were some differences between boys and girls. From time to time, I'm going to share some of my experiences that led me to this conclusion. However, so as to not bias you, I'm going to let you guess, who are the boys in the stories and who are the girls.
Today's Story

When Theo was six, I was sitting on his bedroom floor with him playing with Legos. One of us was building a rectangular structure that looked much like a tall building and the other one of us was building a smaller structure that was "flying" around the room. At first we were both concentrating on our own creations, but then Theo looked at mine and said, "You build just like a girl." He said all of the girls he had seen play with Legos, built something like I did. That surprised me, but he was quite adamant about his conclusion.

You decide: Which one of us made the building and which one of us made the flying object?
_____________________________________________________________________________

In case you want to know: I built the building and Theo built the flying object.