|Montana Contrail Shadow imaged by James Perdue at Culver Pond in Red Rock Lakes National Wildlife Refuge. Image �James Perdue, shown with permission.
The high contrail comprised of water droplets and possibly ice crystals has cast a shadow deep down into the atmosphere. The shadow is a 3D volume of dark air. In contrast, many contrail shadows cast onto lower cloud or haze layers are 2D.
More contrails below...