I know that I have mentioned this before, but Miles is obsessed with space shuttles. But when I say obsessed, I mean that he is completely, head-over-heels in love with the space shuttle. One of his favorite activities is to watch real space shuttle launch videos on YouTube over and over and over. He will literally do this for hours on end until we tell him to turn it off. While he watches the videos, he will hold his toy space shuttle and an airplane belly-to-belly (like the shuttle and the boosters), and move them along with the shuttle on the screen as they take off. It's pretty stinkin' adorable.
If he's not being allowed to watch space shuttles on TV or the computer, then he's pulling out his stomp rocket in the foyer and launching it over and over and over again. He loves to make it fly up and get stuck in the upstairs hall (our house has a very open layout, obviously). Then he will run upstairs and throw it down (despite my requests to not throw it from the second floor) and resume his launching repeats.
It will be interesting to see if he maintains his love for space shuttles and airplanes and rockets. Right now, it's definitely safe to label it as an all-out obsession.