I know everyone has bad airline experiences with every airline - my favorite is probably the one you'll never fly on - so in fairness this has to be taken with that perspective. But this trip was a big reminder of how dismal many of my experiences have been with United. If I'm still mad two days later, I can only imagine that it's gonna stick. I guess what irks me so much with this one is that I played by the rules and still got penalized. I've railed about the luggage fees of some of the major airlines and the added delay and unpleasant boarding and unboardings they cause for all passengers. But once they started being adopted by some other airlines, I did my research and bought carry-on size luggage, learned to pack smaller and tighter so that I could avoid having to pay extra fees. I bought my 3oz bottles and spend the time the night before a flight transferring my liquids and gels to them so that they fit in the proper size clear bag. So Monday I get to LAX with plenty of time, get my boarding pass, and head to the gate. But the passage guard says my bag is too big, I have to go back. I know its not. I've flown with it as carry-on many times by now, including on United. I ask to put it in the measurement display box and show her. She says no - go back and check it. The line that I've already been through is huge. I walk outside and start to go to a skycap line, but decide to go back. She relents and lets me put it on the measurement box - and sure enough, it fits. Its clearly small enough to carry on. And she says "its still too large, you have to check it". Seriously. I'm a little stunned now and protest, but what else can I do? With time ticking, the only option now is to check the bag at a skycap. $17. And another long line. And an extra hour wait added after I get to VA. And on the flight: lots of carry-on bags larger than mine, and plenty of empty carry-on space. So be warned that when flying United, packing a carry-on size bag doesn't mean that they still won't make you pay the cost to check it. Be sure to add $40 to any United search results that come up in your airfare searches - whether you plan to check your bag or not. If that's still your best bet, book it, but go with the proper state of mind. Their flights aren't pleasant, but they'll get you there.