In ArmA III, you will find a large variety of vehicles that you can use.
Control of armored vehicles or regular cars does not require great skills. Just get into the vehicles and drive it around by using the WSAD keys or the mouse.
Helicopters on the other hand, are a bit more complicated. If you've never used helicopters in previous ArmA games, then you should familiarize yourself with the function of Auto-hover. After entering the helicopter, scroll the mouse wheel and then select Auto-hover. This allows you to stay still while you're flying up, no matter which direction you move - the helicopter will automatically return to a stable position. It is recommended to use Auto-hover whenever you're flying up or landing - it simplifies both actions and sometimes can save the lives of you and your passengers. To rise into the air, you have to press the Q key and wait a few seconds. When you're at a safe distance from the ground, turn off Auto-hover and use to WASD keys or the mouse to navigate. The question of whether to use the keyboard or the mouse is fully dependent on you and your taste.
Please note that every helicopter model is different in weight, size or armor, which affects their mobility and resistance. Not every aircraft will be conducted in the same way.