\documentclass{article}
\usepackage{amsmath}
\usepackage[lite]{folarrow}
\begin{document}
Let $\pi\colon E \folrightarrow M$ be a foliated bundle.
Also $M \folleftarrow E$, $E \foldownarrow M$, $M \foluparrow E$,
and in subscripts $A_{E \folrightarrow M}$.
\[
E \xfolrightarrow{\pi} M, \qquad
E \xfolrightarrow[\text{proj}]{\pi} M, \qquad
M \xfolleftarrow{\pi} E
\]
{\Large $E \folrightarrow M$, $E \foldownarrow M$}
\end{document}