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.
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.
City has had many games since it was released. One in particular, The Robot Chronicles, was a cross-over game which saw the City, Racers, and Agents 2.0 all together in Lego City, where the player controlled and unlocked vehicles in each theme to play through a campaign. This campaign/game was also tied into a My LEGO Network The Robot Chronicles campaign- playing the game earned rewards in MLN which could be used in that campaign to eventually get the Key to LEGO City.
The construction of the new airport was carried out during 1964 and the airport opened on 1 November, with one runway at 1660 meters in length and 45 meters width, a small platform where aircraft could be served, and a control tower to the controller. Hans Erik Christensen, the former chief pilot at LEGO became director, and the passengers were handled in LEGO's hangar until the first terminal building was opened in the spring of 1966. The airport was continuously expanded the following years, with new facilities, terminal buildings, lounge, tax-free area and hangars where LC Johansen's studio often participated as an architect (today called the Johannsen Architects), while other work was carried out by the airport's own studio.
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.