In Pocket Planes there are 2 different types of currency; bux and coins. Both have different uses and different ways of obtaining them. Coins are more common, and Bux are more rare and valuable.
Bux are the rarer and more valuable currency in Pocket Planes. Bux can be used to buy planes, plane parts, upgrade planes, remove airplanes from the Hangar, and give costumes to your pilots. You can even convert Bux to Coins! There are also many ways to collect Bux in the game. One way is to buy them in the Get Bux tab in the with real money. Another way to earn Bux is to do special jobs that pay with Bux instead of coins. Additionally, while watching a plane fly, a Bux will sometimes fly across the screen. if you tap on it, it will add it to your Bux bank account. Also, you get 3 Bux every time you increase a level.
Coins are the more common currency in Pocket Planes. Coins can be used to buy Airports, upgrade airports, and advertise airports. Coins can be collected in many ways. One way is to deliever Jobs. Another way is to watch your planes fly. A third is to use the Bank to trade 1 Bux for 500 coins. Occasionally, a coin or big coin will fly by; tapping on them adds 1 and 10 coins to your Coin bank account respectively.