the.com/boarding pass

means The ticket issued at check-in that proves you have a seat on a specific flight and tells you when and where to board.

from A straightforward compound: 'boarding' (getting onto a ship, train, or plane — from 'board,' originally a ship's plank or side, so to 'go aboard' meant to step onto that plank) plus 'pass,' a document granting permission to go somewhere, from Old French 'pas' meaning a step or passage, rooted in Latin 'passus.' The term grew alongside 20th-century mass air travel, when airlines needed a simple word for the slip that let you past the gate and onto the plane.