Thank you all for your advice.

I have not bought the cat carrier yet and have been debating whether to buy hard or soft. I am worried about the carrier fitting under the seat, and that's one reason I'll book F. I've been in F on flights where I couldn't fit my computer carry on under the seat in front of me--same carry on fit under CRJ-700 F seat. I have bought a cat harness and a leash.

I am moving for my husband's job, and my travel date is flexible. I think that UA limits animals on flights and will call ASAP for my reservation.

Even though my cat is almost perfect , I do worry that he will bother other PAX and I wouldn't want to listen to his fussing for hours. I'll ask the vet about a sedative. I am hesitant to give a sedative to him, but I have no idea how he'll react on a plane. It's a long flight from SYR to SEA, and I'll have a connection in ORD or IAD.

Any more advice or comments?

Thanks!