When you complete a contract, you unlock a new route.
Each new aircraft or new license gives you a certain number of new unlockable routes. You will need more licenses or aircraft to proceed with activating a new contract, as otherwise you will not be able to unlock more routes.

If you do not have enough resources to unlock anything, you can choose to use AC Credits, or you can always fly for other airlines to get more Flight Points or money from them. (You will not get routes for your airline if you fly for others.)

We recommend you search for some YouTube tutorial videos made by our players, which might also guide you through the world of Airline Commander!

https://www.youtube.com/results?search_query=airline+commander+tutorial