Both construction are build on a temporay server map in 2011. At this time creative mod wasn’t in the game so flying wasn't possible and we needed to have a mod to get the item without crafting/farming them.
The Yamato was building on a thursday-friday in july 2011, I'm still surprised that I did it so fast, I was alone except for the design of the chimney.
The millitary base was build not far, it had some detail like a trap door at the entry and was fully functionnable with the warplane and tank from the Flan's WWII mods