HideFlags.HideInHierarchy  

// Creates 5 planes and hides them from the Hierarchy in the Editor.

function Start() {
for(var i : int = 0; i < 5; i++) {
var createdGO : GameObject = GameObject.CreatePrimitive(PrimitiveType.Plane);
createdGO.hideFlags = HideFlags.HideInHierarchy;
}
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
void Start() {
int i = 0;
while (i < 5) {
GameObject createdGO = GameObject.CreatePrimitive(PrimitiveType.Plane);
createdGO.hideFlags = HideFlags.HideInHierarchy;
i++;
}
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

def Start():
i as int = 0
while i < 5:
createdGO as GameObject = GameObject.CreatePrimitive(PrimitiveType.Plane)
createdGO.hideFlags = HideFlags.HideInHierarchy
i++