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JWST provides an unprecedented opportunity for unbiased surveys ofH$\alpha$-emitting galaxies at $z>4$ with the NIRCam wide-field slitlessspectroscopy (WFSS). In this work, we present a census of Ly$\alpha$ escapefraction ($f_{esc, Ly\alpha}$) of 165 star-forming galaxies at $z=4.9-6.3$using their H$\alpha$ emission directly measured from FRESCO NIRCam/WFSS data.We search for Ly$\alpha$ emission of each H$\alpha$-emitting galaxy in VLT/MUSEdata. The overall $f_{esc, Ly\alpha}$ measured by stacking is $f_{esc,Ly\alpha}$ is $0.090\pm0.006$. We find that $f_{esc, Ly\alpha}$ displays astrong dependence on the observed UV slope ($\beta_{\rm obs}$) and E(B-V), suchthat the bluest galaxies ($\beta_{\rm obs}\sim-2.5$) have the largest escapefractions ($f_{\rm esc, Ly\alpha}\approx0.6$), indicative of the crucial roleof dust and gas in modulating the escape of Ly$\alpha$ photons. $f_{esc,Ly\alpha}$ is less well related to other parameters, including the UVluminosity and stellar mass, and the variation in $f_{esc, Ly\alpha}$ with themcan be explained by their underlying coupling with E(B-V) or $\beta_{\rm obs}$.Our results suggest a tentative decline in $f_{esc, Ly\alpha}$ at $z\gtrsim 5$,implying increasing intergalactic medium attenuation towards higher redshift.Furthermore, the dependence of $f_{esc, Ly\alpha}$ on $\beta_{\rm obs}$ isproportional to that of the ionizing photon escape fraction ($f_{\rm esc,LyC}$), indicating the escape of Ly$\alpha$ and ionizing photon may beregulated by similar physical processes. With $f_{esc, Ly\alpha}$ as a proxy to$f_{\rm esc, LyC}$, we infer that UV-faint ($M_{\rm UV}>-16$) galaxiescontribute $>70\%$ of the total ionizing emissivity at $z=5-6$. If theserelations hold during the epoch of reionization, UV-faint galaxies cancontribute the majority of UV photon budget to reionize the Universe.

Quantifying the escape of Ly$\alpha$ at $z\approx 5-6$: a census of  Ly$\alpha$ escape fraction with H$\alpha$ emitting galaxies spectroscopically  confirmed by JWST and VLT/MUSE