They still store unused aircraft (mostly freighter and airliners) at Kingman, at least there's a heckuva lot of them there in the dry desert air. You can see the from I-40 as you drive in from the eastern side. I think most of them are freight aircraft, but I didn't get close enough to tell.
Kingman was a huge depository for WW2 aircraft. B-17's, BT-13's and whatever else. There are photos of that.
Here's a link to one article:
https://airplaneboneyards.com/kingman-arizona-airplane-boneyard-storage.htm
