I wasn't aware of the draco meaning. I found the meaning of soldier for Dragoun at the following site:http://zlimpkk.tripod.com/Genealogy/czechsurnames.html
That is for Czech surnames. My grandmother told me that her dad changed his name to Dragon because he was in trouble. I would suggest trying to find out where your ancestors are from first and then trying to find out the meaning of the name.

Good luck
Brian