The Vimana is recorded in ancient Indian texts as being a flying machine, and its features are described in detail. Below is just one source on the internet.
http://www.electrogravity.com/index2.html
"The crafts primary drive supposedly used the metal Mercury in a closed system that heated the Mercury to a high heat. This vapor was set into oscillation through a set of coils wound in caduceus fashion. (Wrapped around each other like two snakes, the heads pointing at each other.) Please see the picture CADUCEUS (below) from page 248 of the related book, "Vimana Aircraft of Ancient India & Atlantis", by David Hatcher Childress."