Originally Posted by
StingWest
Generally, it is the Length of the bag rather than the thickness that causes most problems. This causes people to have to swing the bags around and take up almost 2 "slots" for one bag which seems unfair to me as it often requires people following the rules to have to check their bag.
Exactly correct.
If the length (= long axis) of the rollaboard allows it to fit in the overhead perpendicular to the aisle of the aircraft, then the maximum number of bags can be loaded. Width is the next most important dimension because overly wide bags would decrease the total number of rollaboards that could be stowed. Thickness or height is the least important dimension since most overheads have plenty of height such that small computer bags etc. can usually be placed on top of rollaboards in a full bin. However, in no case would the height/thickness of a bag affect the maximum number of rollaboards that could be stowed, since the unused headroom is not fungible.