nostr:npub17sha6ku2fxgt7k268u5kedl5pn25dqrd6v9eqem7kj3s2248mnfs7x6e06 could be that when you go up a ‘flight of stairs’ when you reach the top and stop you have ‘landed’, hence area called ‘landing’. 

Sounds very modern if we think of it in relation to planes, but actually birds have been around longer than two storey houses!