There is a lot of ways to do that in Unity.

I would use this:

Tag your Tornado as "Tornado".

The OnTriggerEnter function has a parameter that you have to use to check what is the collider object.

(I use C#, but just look at the LOGIC, and not the syntax)

//This should be attached to your car
void OnCollisionStay(Collision obj){
  //obj will be the Tornado, right?
if(obj.gameobject.tag == "Tornado"){
 YouCarFlyAwayHere();
  }
}

You could also use OnCollisionEnter(). But that way you maybe should implement OnCollisionExit() as well.

I hope I helped.

Good Luck.

So, I tagged the tornado as Player, and here is the script I used:

function Update () {

//This should be attached to your car

void; OnCollisionStay("Tornado");{

//obj will be the Tornado, right?

if(obj.gameobject.tag == "Player");{

info.gameObject.AddComponent("RandomFlying");

}

}

}

This gave me these errors:

Assets/Scripts/TornadoScript.js(6,1): BCE0043: Unexpected token: if.

Assets/Scripts/TornadoScript.js(7,46): BCE0044: expecting :, found ';'.

ummmmm these are the 2 errors I cant figure out??? any help?

Here try this.

void OnTriggerEnter (Collider info) {
    if(info.gameObject.tag == "Car")
    {
        info.gameObject.AddComponent("RandomFlying");
    }
}

void OnTriggerExit (Collider info) {
    if(info.gameObject.tag == "Car")
    {
        info.gameObject.GetComponent<RandomFlying>().Destroy();
    }
}

There we go, now all you need to do, is to set your tornado's collider to isTrigger. Then give your car, the Car tag, and your all set :)