In December 2012, the BBC's More or Less radio program asked the Open University's engineering department to determine "how many Lego bricks, stacked one on top of the other, it would take for the weight to destroy the bottom brick?" Using a hydraulic testing machine, the engineering department determined the average maximum force a 2×2 Lego brick can stand is 4,240 newtons; since an average 2×2 Lego brick has a mass of 1.152 grams (0.0406 oz), according to their calculations it would take a stack of 375,000 bricks to cause the bottom brick to collapse, which represents a stack 3,591 metres (11,781 ft) in height.
Lego pieces of all varieties constitute a universal system. Despite variation in the design and the purposes of individual pieces over the years, each piece remains compatible in some way with existing pieces. Lego bricks from 1958 still interlock with those made in the current time, and Lego sets for young children are compatible with those made for teenagers. Six bricks of 2 × 4 studs can be combined in 915,103,765 ways.
Stickers are used for decorations for the outside of the plane. I like how the stickers for the outside match colours with the piping on the plane. I found the sticker for the top of the door to be a little big; if you line up the orange on the bottom of the stickers with the orange on the plane the sticker overlaps a bit at the top. The stickers for the nose of the plane are not as difficult to apply as I thought they would be. They do seem a bit superfluous, though they do make the plane look nice. The plane is finished with the tail fin, that uses yet more stickers. It is interesting that this plane actually uses more stickers than the Friends plane does.
Other than the planes, I do find it unfortunate that the Friends set focuses on shopping and food like so many Friends sets, and I also think it is unfortunate that the City terminal only has the basics of the airport structure in the control tower and service truck. Having a control tower for the Friends set would have been great. Having a gift shop/cafe for the City terminal would have been a worthwhile addition and not something we have seen in many City sets.
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.