Choosing a random GameObject out of an array?

I am making a script that lets an airplane choose the city it will land in, using an array. This is what I have-

 #pragma strict
 
 var allcities : Array;              //an array of all the cities on the map
 var takeoff : String;              //where the plane has taken off from
 var landing : GameObject;           //where the plane will land
 
 function Start () {
     allcities = GameObject.FindGameObjectsWithTag("City");    //putting all the cities on the map into an array
     var i = Random.Range(0, allcities.Length);
     landing = allcities[i];
 }

However, when I run the script, the landing var in the inspector remains the same. No errors or warnings occur, just the script does not seem to function. I threw in some Debug.Log's, but I cannot seem to find the problem.

Before that, I had condensed the script to this-

 #pragma strict
 
 var allcities : Array;              //an array of all the cities on the map
 var takeoff : String;              //where the plane has taken off from
 var landing : GameObject;           //where the plane will land
 
 function Start () {
     allcities = GameObject.FindGameObjectsWithTag("City");    //putting all the cities on the map into an array
     landing = allcities[Random.Range(0, allcities.Length)];
 }

The only reason I broke it up was so that I could find the problem easier.

Any ideas?

Only Javascript please

Fairly Urgent