Or loading the plane back to front, no exception, though I suppose with #3 it might not matter. The zone system and the way most airport terminals are designed

Or loading the plane back to front, no exception, though I suppose with #3 it might not matter. The zone system and the way most airport terminals are designed make queueing and getting on the plane a horrendous cluster fsck. Airports remind me of legacy software in many respects: they do things the way they do because they are building on foundation of garbage processes.