My husband and I took separate flights with American Airlines from LAX to Charlotte. I had a smallish cat and husband a 21lb dog. Both sailed through fine and both fine on the flight - no problems whatsoever. Staff were great. No way the dog could “stand up and turn around” but she’s an old dog and doesn’t do much moving around anyway. Cat surprised me by being quite settled (once I got her in the carrier!). It’s a 5 hr flight - plus bus ride to airport and car journey beyond but with one side unit opened on one side on the flight she was fine. It was like her conservatory. Fitted under the seat fine (window seats provide more space). I was in Economy but chose a seat with extra leg room. At LAX I had to go into a little room with a member of staff, take her out of the carrier so it could be scanned. All fine. Dog was also great on the flight - AA staff took a pragmatic view with what was a very well/behaved and sleepy dog. Great value for money. Easy access to carrier - there are a few you need to ensure are all closed up. Pets looked and seemed very comfortable. I used Feliway for the cat (it only lasts 4 hours but settled her in perhaps).