Wings Of War Finding the tanks in Unrestful Rest
Like the Big Bertha cannons, the tanks are sequestered safely away. On your map, in the circle you need to search, there is a circle made by the lines that indicate roads. This is a town. Search there, flying near the chapel, and the tanks will appear.
The image featured at the top of this post is ©The Legend of Heroes: Trails of Cold Steel III key art / Original