I remember watching a documentary years ago which said that based on the laws on physics, it was enitirely possible to have a creature the size of a Boeing 747 Jumbo jet that was still capable of flight. I don’t remember if they meant gliding or proper, muscle-powered, wing-flapping flight, but it was flight nevertheless.
So is this true? Just how big could a bird get before its sheer size made flight impossible?
Does it have to be designed like a bird?
I imagine a creature more like a balloon (something like a cross between an octopus and jellyfish). It breaks down water into hydrogen and oxygen, stores the hydrogen in a bladder, and floats around hoping not to get hit by lightning.
Why not Hindenburg sized?
The problem I see with such a creature (not the balloon type - that’s just silly*) is the supporting structure would have to be stronger then the materials currently in use (bone) and still be light weight.
Err, k2dave, don’t you mean Titan? It would be pretty easy to have a balloon creature floating about in a dense methane atmosphere in low gravity. Jupiter itself would be another possibility. Carl Sagan went into this in Cosmos.
Such a creature would still have to contend with the financial difficulties of buying two tickets for itself at the Southwest Airlines counter.