Is it possible to define vector bundles as particular instances of étale bundles?
An étale bundle is a bundle $p:E\rightarrow X$ which is a local homeomorphism (as in Maclane-Moerdijk): every $e\in E$ has an open neighborhood $V$ s.t $p(V)$ is open in $X$ and $p|_V$ is a homeomorphism.
Nontrivial vector bundles are never étale.
From Maclane-Moerdijk p88: