Carry-on luggage may get smaller
It’s already happening in U.K. and Europe, with Wizz Air and Ryanair reducing the size of their allowed carry-on luggage. This may have a domino effect, with other airlines following their example.
Such a change means that the standard carry-on cases that most people have will no longer meet the requirements and specifications. This gives the carriers the opportunity to charge extra for standard carry-on luggage, even if these fit under the seats.
We might not like it but it’s gonna happen! So, check the luggage policy of the airline you’re going to use, thoroughly to avoid any unpleasant surprises.