"legitimate interests" are subject to interpretation on purpose; either legitimate interests on a given instance are lawful, or you're better off relying on consent, since your interpretation and the regulator's interpretation may be different. Check page 7 of https://www.edpb.europa.eu/system/files/2024-10/edpb_guideli...
What's 'legitimate' and what isn't is up for interpretation, but the question of whose interests is clear in the text of the GDPR itself, and it's the controller's (or a third party's) interests which could form the basis of lawful processing.
Interestingly, the GDPR specifically does not include 'benevolent' processing (i.e. processing for legitimate interests of the user) as a lawful basis.
Carryons are by far the best experience for a passenger - your bag is there with you and you don’t have to arrive at the airport early, nor wait around at baggage claim. All business and frequent travelers would pay extra for this.
Meanwhile, carryons are worse for everyone else, and for the airline! They massively slow down the boarding and deboarding process while you wait for people to heft their massive suitcases up into the bins.
Fewer carryons means faster turnarounds which means more profit.
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