In Airport City and Airport City HD for the iPhone, iPad and Android, just like in the Facebook version, there are two main types of currency. The main currency is coins. This is a currency you can earn for doing most things in the game, and you can use it to buy most of what you need. Airport Cash is the premium currency, and you can use it to purchase many things that will speed up your progress in the game. This includes items that are necessary to complete a collection, repair airplanes or give you a bonus booster that you couldn’t get otherwise, as well as instant fuel and passengers. Read on to find out how to get more of both!
To maximize your coins, the best thing to do is to maximize the amount of businesses that you have, to the extent that you need to build more roads to accomodate them. Build businesses that fit your playing style, whether that be Eateries that you can collect from every minute or two, or businesses such as Sports Shops and Movie Theaters that you can only collect from once per day. These are your main avenue for collecting coins.
In addition, maximize the amount of runways that you have at any given time. Find room for them in any way possible, so that you can not only send off multiple flights at once, but accept multiple guest flights at a time. Have at least 3 runways to be able to maximize your flights.
There are two different ways to get Airport Cash. One way is, unfortunately, to buy it. The other way to get it is to gain an experience level. Every time that you gain one experience level, you will gain one airport cash as a reward for that level that you gained.