Well, leaving aside the problem of taking off (which today is improving thanks to electric motors), I guess one could say that gliders[1] are the closest we can have to human-powered flight and it's highly efficient in terms of energy consumption
> It's "not very good" not because people are this or that...
Denying reality is for daydreaming; it will not get anything invented. Sufficiently advanced technology may be indistinguishable from magic, but it isn't actually magic.