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.
Primary concept and development work takes place at the Billund headquarters, where the company employs approximately 120 designers. The company also has smaller design offices in the UK, Spain, Germany, and Japan which are tasked with developing products aimed specifically at these markets. The average development period for a new product is around twelve months, split into three stages. The first stage is to identify market trends and developments, including contact by the designers directly with the market; some are stationed in toy shops close to holidays, while others interview children. The second stage is the design and development of the product based upon the results of the first stage. As of September 2008 the design teams use 3D modelling software to generate CAD drawings from initial design sketches. The designs are then prototyped using an in-house stereolithography machine. These prototypes are presented to the entire project team for comment and for testing by parents and children during the "validation" process. Designs may then be altered in accordance with the results from the focus groups. Virtual models of completed Lego products are built concurrently with the writing of the user instructions. Completed CAD models are also used in the wider organisation, for marketing and packaging.
Anyway, I think this may be my favorite LEGO City air terminal yet! It may not be as big as some previous ones, but it feels really coherent. The plane is nice as well with its white, orange, and blue stripes. I agree that Heartlake City Airport's plane has a cozier and more detailed interior, though. It does really highlight some of the differences between Friends and City, with City opting for capacity over comfort and function over flair.
In 1997 they had an architectural competition for a new 430,000 ft² (40,000 m²) passenger terminal, designed to serve 3.5 million passengers a year, north of the original airport. KHR Architects won the assignment and completed the construction in co-operation with COWI, and at the end of May 2002 the new passenger terminal was put to use, as the first phase of the future expansion, which is scheduled to take place north of the start and runway, while air cargo services, business and private aviation will continue to be served from the existing buildings south of the runway. In connection with this expansion, the largest since the beginning of the airport, it was with effect from 1 January 1997 turned into a Joint-stock company, Billund Airport A/S, with the former members Vejle County and municipalities Vejle, Kolding, Grindsted, Billund, and Give as shareholders.
Even in terms of play value it mostly seems to be a trade-off — 60104 loses the vending machine, cafe, baggage x-ray scanner, and a few seats on the plane but gains a baggage conveyor, a restroom, a refueling tank for the plane, an additional minifigure, and more seats in the waiting area. It's pretty nice to see the value of a LEGO air terminal remain fairly stable even though the price has not increased.
The remainder of the build is the control tower and terminal building. First there is a metal detector screener leading to the waiting/secure area of the airport, which seems taller than it needs to be for the minifigures. I think the same effect could have been made with half the height, except that would not allow for an impressive height for the overall tower. However it does seem to be similar to many modern airports with the high ceilings. This area also seems to be someplace to check luggage as evidenced by the rather nifty conveyor belt that comes in a full part. The moving parts of the set include a revolving door (a very tall one, for the first floor) that leads from the secure area of the airport out to the tarmac, and of course the conveyor belt.