[ EU ] Explain the disappearance of the Type-25 Troop Carrier from Halo 2 , 3 , ODST And 4 .

`` You know, I never really thought about it.'' 
 
 The Sangheili warrior leaned back in his chair. In his fourth month of deployment on the Human world of Sentry, he'd finally found a way to be comfortable in the human chairs. 
 
 `` But it did happen, right? We....well....people living on Reach saw them. But as soon as the battle of Earth happened, no more Spirits.'' 
 
 Usze'Tzhara removed his traditional helmet and moved his mandibles. He leaned closer to the group of soldiers he sat with. 
 
 `` We're not that different, you know.'' Usze remarked, `` We had issues of moving weaponry too. Did each of your ships have Hornets? Did any of you ever see a Vulture in combat? What about a Wolverine, or a Mongoose?'' 
 
 The soldiers asked around the table. No one who had served in the battles near Earth had seen a Vulture in combat. A veteran of the Battle of Installation 00 also talked about the Chopper he'd once driven, and none of the men who had fought the forerunners had seen or driven one. 
 
 `` It's not a mystery,'' said with an ease an Elite rarely had before peace time, `` and it was n't a matter of politics. Sometimes, your vehicles are elsewhere.'' 
 
 His translation unit did n't quite have an effective explanation, but he heard one of the troops state loudly `` Excrement of a Bovine organism.'' He continued eating instead of responding.
