To see the list of routes you’re currently connected to, open up the airport window and click on the “ROUTES” tab at the bottom. When you connect two cities, you’ll only have one airplane moving back and forth on that route. But, if you want to add more planes to a route, it’s really easy! Just click on the “+” button in any blank cell next to the route you want to add a plane to. You can add up to a maximum of 5 airplanes on each route.
If you want to upgrade one of your airports, there are two ways to do it. First, you can click on the airport pin on the map and look for the “Upgrade” button. Alternatively, you can go to the upgrade screen by clicking on the arrow button in the footer. Here, you’ll see a list of all your airports, and you can quickly upgrade them without having to open each one up separately.
To connect two airports, simply drag your finger from the outbound airport to the destination airport on the map. As you drag the line, you’ll see an approximate cost for the route. When you get close to the destination airport, you’ll feel a haptic feedback on your device. This means that you’re about to connect the two airports. If you’re happy with the route and the cost, just release your finger near the destination airport to connect them. You’ll see a confirmation pop-up asking you to confirm the purchase of the route. If you change your mind, you can opt out of it.