You can pretty easily go about adding and subtracting from an array, here's an example

//this is the array you will be modifying, you will need to get a hold of it first if it is in another script
var array1 : gameObject[];

// this function will need to have the object that is being added passed in to it.    
function addToArray (obj : gameObject) {
   array1.Add(obj)
}

And as far as subtracting a gameObject goes you could try removing it from the array before you destroy it.

// this function will need to have the object that is being removed passed in to it.
function destroyObject (obj : gameObject) {
    var objectIndex : int;
    // find the index of the object to be deleted (what number it is in the array)
    for (var i : int=0 ;i<array1.length; i++){
        if(array1[1] == obj)
            objectIndex = i;
    }
    //remove the object from the array
    array1.RemoveAt(objectIndex);
    //now destroy it
    Destroy(obj);
}

There is no "Add" method on the builtin array type! The above will not compile, even if you do use "GameObject" instead of "gameObject".

However, try this:

var array1 : GameObject[];

function addToArray (obj : GameObject) {
   array1 += [obj];
}

Voila! Note that this is less efficient than implementations such as a fixed-maxsize array with an end cursor, but I tend to use it when the adding to the array is not performance-critical (eg. bullet is created), thus making it easy to use these fast builtin arrays, so that the performance critical array-READING code (eg. for every bullet every frame, check for hits).