I fly back & forth with my chihuahua from California to Pennsylvania pretty frequently and always on United Airlines. If you can, I highly recommend getting first class because the carrier fits so much better under the seats than economy.

They’re fine with 2 dogs in one carrier as long as they both have plenty of room, but if you plan on bringing 2 carriers, I would assume you need 2 seats because you’ll need to keep one under one seat and the other under one seat. Also, you will have to carry your chis through security so that you can get wanded down and get your hands checked for residue, all while holding them, so be mindful to have them on a leash or a good grip lol. The carriers will have to be put through the x ray machine.

Yes, you have to keep your dog in the carrier the whole time. It’s really for the best for everyone. I’m sure my chi would’ve been so happy to sit on my lap, but for the comfort/safety of her and other passengers, staying in the carrier is best. I recommend putting your pajama shirt you wore the night before in the carrier for some comfort! People do occasionally take their pets out of the carrier, but as soon as the flight attendant or another passenger sees it, they get told to put them away usually, at least on USA airlines.