Airplanes : first planes were flown by military ex horse riders (because of the sword, and more right handed people), when the question of choice came, the left was chosen.
Helicopters : first mass production 2 blades helicopter had a nasty consequence in unloaded g's manoeuver and the consequent tail strike, the blade momentum would get more chance to strike the cockpit on the l/h side, hence the choice. still carried todayon multiblades...
airbridges, traffic patterns and the like came later and were chosen accordingly...
AFAIK