I checked carry-on rules at 75 airlines. The carry-on wasn't the trap.

I watched someone put their backpack in a sizer at a gate a couple of months ago. It was less than an inch over the personal item rule. The agent apologized, said no, and made her check the bag. She walked away frustrated. I walked away thinking about the data. That moment kicked off a small project. I pulled the published carry-on and personal item rules for 75 airlines and tested both. The carry-on data came out about how I expected: 14 of 75 airlines reject a standard 22 by 14 by 9 inch suitc