The recent design of a sail plane that can reach 90,000 feet suggest that there could be a competition for altitude in the category that might reveal new technologies capitalizing on the properties of the atmosphere and on other innovations.
All planes look more or less like a bird. None look like a frizby. Gliders do not use environmental energy or atmospheric substances or even lighter-than air gasses. It seems to me that there are possibilities that have not been looked at.
Why not achieve low orbit over a period of a month or two instead of an hour?