Why boarding happens in groups at all
Boarding in a defined sequence, rather than all at once, keeps the single jet bridge and aisle from becoming a bottleneck — the groups exist primarily to manage physical flow, not to create a sense of priority on their own.
What usually determines the early groups
Travelers needing extra time, families with young children, and passengers in forward cabin sections are typically invited first, generally followed by the back of the aircraft before the middle, to reduce aisle congestion during loading.
Why boarding early is not always better
Boarding as late as reasonably possible, within your assigned group, means less time sitting in a cramped seat before departure — a strategy that trades overhead-bin space for comfort and works best when carry-on space is not a concern.
Questions people ask
Does boarding order affect overhead bin space?
Yes — bins near the back of the aircraft and in the middle sections fill up fastest, which is part of why boarding order so often tracks seating section.
Is it worth lining up before your group is called?
Generally not — standing in a queue before your group is called rarely saves meaningful time and mostly adds standing time instead of seated waiting.