I bought a package subscription, can I use it to both Air Navigation Pro iOS and Android?

Of course. You simply need to connect with the same Air Navigation Pro account that you used in your first device. You will be able to restore all the purchases you made in your first account. In the application, make sure that you are connected with the same account (Configuration > Account). 

iOS: Configuration > Store > Restore
Android: Configuration > Installed data > Restore