How to sync contacts?

By default, your contacts will not sync unless you install an app that will allow to sync them. You can either find the Google contacts sync on APKmirror or by following this link. Use the app corresponding to your Android version.

Is Flarm working everywhere?

For more details about Flarm, Fanet and Livetracking, check this FAQ. The Flarm module integrated in AIR³ 7.3+ is using 868 MHz data communication frequency currently. The Flarm module integrated in AIR³ 7.3+ V2 uses all frequencies used by Flarm worldwide. The module selects automatically the right frequency. 868.2-868.4 MHz (Europe, Africa)869.2 MHz (New Zealand)902-928 Read more about Is Flarm working everywhere?[…]

Do I need an option?

By definition, an option is not necessary. However, options are available in case you want to take advantage of specific features. You can find all options here: http://shop.fly-air3.com/shop/category/air3-19. Check the accessories page to know more about each option.