The New York Times reports several domestic airlines are considering a flat fee for carry-on bags that exceed posted size limits.
Alaska Airlines charges a $25 fee at the gate for oversized carry-ons.
Spirit Airlines charges $45 to put any carry-on bag in overhead bins. It plans to raise that fee to $100 in the fall.
Other airlines are considering carry-on charges at the gate as they look for ways to increase revenue. It's also a way to deal with the growing number of passengers who are carrying bags on board instead of checking them.