\documentclass{article} 
\usepackage{amsmath}

\newcommand{\bqy}{\begin{eqnarray} }
\newcommand{\eqy}{\end{eqnarray} }

\newcommand{\bal}{\begin{align} }
\newcommand{\eal}{\end{align} }

\begin{document}

\bqy
1 && 2\\
3 && 4
\eqy

\bal
1 & 2\\
3 & 4
\eal
% \end{align}


\end{document}