Used a Monos Carry On Pro (spec’d at 22x14x9) for a recent U.S.-UK jaunt, and neither AA nor BA had any size concerns. Observation, the Pro’s pocket comes at the cost of interior space to a somewhat greater extent than I expected. However, an external pocket is sooooo much more convenient. It was a 777 with AA, a BA CityFlyer E190 and a BA B737. Fit was fine.