Some aviation experts contend that the Boeing 757 is more efficient than its sibling, the Boeing 767. One reason for this may be because it has a smaller cross-sectional area and thus less drag as well as higher stall speed due to having greater wing loading. What’s more is these two planes have shared common type rating since 1974! Airlines enjoy flexibility in assigning crews when both aircraft are part of their fleet or even swapping between them if they so choose