It was designed lower to be easier to work with ground handling and servicing. This lead to a few different designs of plane-deployed airstairs and made it po

It was designed lower to be easier to work with ground handling and servicing. This lead to a few different designs of plane-deployed airstairs and made it popular with Alaska Air and other airlines serving small airports. https://en.wikipedia.org/wiki/Boeing_737#Background https://en.wikipedia.org/wiki/Boeing_737#Background