Correct - the hanger can only accommodate the biplane. That having been said, in order to accommodate the other aircraft too the hangar would have to be huge, with an enormous footprint, and a substantially increased parts count. As a result, I'd estimate a price up to double the current RRP which I suspect few of the target market would pay. LEGO therefore got the size of the hanger right IMHO.
Basically, the only thing that the two sets have in common is that they both have planes. However there is quite a bit of difference on the inside of the planes. There are a lot more details in the Friends plane. In addition to the seats, there is a rolling service cart complete with refreshments, emergency lighting as well as a larger galley and lav in the back of the plane.
Unlike the City set, there is no control tower or truck that services the plane. Instead, there is a passenger check-in/baggage carousel, a rolling staircase to gain access to the plane, plus the airport entrance that includes a gift shop and a café (or, one could argue, something that is very much like many other Friends sets out there). There are only three mini-dolls in this set compared to the six in the City set.
The build itself is good fun, as it should be, and engaging enough to be interesting. The only thing that I started to find a little boring was the Airport Control Tower, but then its top redeemed it. Naturally, the best thing to build is the Giant Man figure. The techniques used to make it posable, like a regular Lego minifigure, were brilliantly thought out. I hope to see more like this, perhaps in a Galactus set, although I doubt that’ll ever happen.
Since around 2000, the Lego Group has been promoting "Lego Serious Play", a form of business consultancy fostering creative thinking, in which team members build metaphors of their organizational identities and experiences using Lego bricks. Participants work through imaginary scenarios using visual three-dimensional Lego constructions, imaginatively exploring possibilities in a serious form of play.