Any advice for ensuring your carry-on gets carried on? How can you convince the flight attendant that it fits? On my most recent Vegas trip, we had a problem with carry on luggage. It was a full flight and they asked for people to volunteer to check their bags at the gate because the overhead space would be limited. Fine. That happens all the time. My backpack was stuffed, but I never get any trouble in these situations. I've always been able to cram it under the seat in front of me. But I volunteered to check it, since I didn't need it during the flight and we had checked a different bag at the ticket counter and would need to visit the bag claim anyway. However, the flight attendant at the gate was adamant that my girl had to check her small travel case. It had wheels and a plastic shell. It easy fit in the size-checker, but I guess that's for the overhead bin? The thing is, it is obviously smaller than my backpack which I have successfully put under the seat probably 100 times. I understand that the hard shell makes a difference, though. I've seen this before, too. Once, on a morning business flight in Boston, there was a extremely long line at the security checkpoint. The girl ahead of me in line had a small, hard plastic case similar to what I described above. Again, it looked considerably smaller than my giant overstuffed backpack. It took probably 30 minutes before finally reaching the TSA representative who inspects your ID and boarding pass. Well, there was another airport employee directing people in line on this and that. She came up to the girl in front of me and told her she had to check her bag. Since the line was so long, this would result in the girl missing her flight, but no mercy was shown. I honestly feel like the airport employee was having a bad day or something and deliberately taking it out on someone. In retrospect, I should have stood up for the girl and said that she should take the bag through security and check it at the gate if it was necessary, instead of having to go all the way back through the line.