Originally Posted by
AuntieMame
Actually, the carry on limit is set by the Federal Government (Department of Homeland Security).
You're technically incorrect.
The current limit was imposed in early October, 2001, by edict from Norm Mineta, then-Sec of Transportation (following input from an industry task force, which included Bob Baker of AA). All airlines were required to modify their carry-on policies to his edict and they've remained there ever since.