There is a great wealth of user guide information written to help you, whether you are new to the game of Airport City or you are much further along. The user guides will provide you with a broad spectrum of information across many subjects.
The user guides will provide information, guidance, advice, prices (airplanes, structures, helicopters), flight locations, Space Program, daily discount sales, world map locations, discount super sales, land expansion discount sales, airship store sales, alliance groups, game store sales, on screen game display counters and icons.
There are also a 'How To' series of user guides e.g. design your signature page, obtain gold and silver tokens, take screenshots of your game, contact technical support for help, collect green notes, collect game codes, obtain building chests, obtain helicopters, purchase silver and gold subscriptions, obtain mystery chests, reclaim valuable land, obtain game play money, obtain destination flight map.
There are also general guides from forum members that suggest some strategy and answer frequently asked questions. You can find these guides here