Margaret Atwood vs. debt

[David Gentle]

> Another friend of mine used to maintain that airplanes stayed up in
> the air only because people believed -- against reason -- that they
> could fly: Without that collective delusion sustaining them, they
> would instantly plummet to earth. Is "debt" similar? In other words,
> perhaps debt exists because we imagine it.
>
Given that most people didn't believe that humans could fly surely  planes 
would never have got off the ground in the first place?
David Gentle