Unless you're moving to Seattle, of course, is there any chance that you could have someone look after your cats? Maybe it would be less stressful for you and your cats that way
I just traveled with my kitty for the first time a couple of days ago. He flew once before (on his way to me). He traveled in the cabin both times (once on UAL, once on US).
I have to say that the airlines didn't seem too concerned about checking anything about the cat. Kitty had a health certificate both times but no one asked for them. I know this has happened to other folks as well. I got the certificate to be on the safe side.
Not that I'm encouraging naughty behavior...but if the airline allows two cats to travel in one bag under certain circumstances (you said an exception is if the cats were both under 6 mos), then maybe you can make reservations for the cats and put them in a carrier large enough for the two of them. Maybe the agent won't try to verify your cats' ages. If the agent asks for the health certificates though he/she will see the ages.
A few times when a friend of mine was traveling with her cat, no one even asked for the fee! She made reservations for the cat but when she checked in at the ticket counter the agents didn't mention the cat. Twice now (once just last month) she hasn't mentioned the cat and just took her boarding pass and headed to her flight. The cat was accounted for in the airline's sytem but at the airport it's like he didn't exist. BIG CAVEAT: If you try any of the above, you risk having an agent take one look at you and your contraband kitties and tell you you can't get on your flight
Now that I think about it, if at the ticket counter I hadn't verified that my cat had a space on the flight (I made a reservation for him), I really don't think the agent would have said anything to me either! Go figure. I should add that my cat and my friend's cat are pretty mellow, and we have carriers that look like a gym bag and backpack.
Some general tips if you do fly with your cats: A man who travels with his 13 year old cat several times a year said that if a cat travels well in a car then air travel should be no problem. He might have a point. If you haven't taken more than a really short trip in the car with your cats, it might be worth it to see how they react during a longer drive.
All airports that I know of in the States make you take your pet out of the carrier and walk him/her through the metal detector with you. Just the carrier goes through the x-ray machines. Frannie is right - harnesses and leashes are an excellent idea. Having a cat out in an airport can be quite an experience. My friend told me that when he brought my kitty to me that kitty tried to make a break for it at security. But, when I went through security with the kitty he was fine. He seemed to be almost relieved to get back into the carrier.
I've read that most cats are good air travelers since it's a survival tactic to stay quiet (and safe) if they can't fight a threat or run from it (this assumes that all of the activity on the plane is the perceived threat).
Check to see if there are other pets on board that are near you. On my flight, there was a dog in the row ahead of me. I heard scratching noises and thought it was my cat. When I checked on him, he was practically asleep. Then, I heard the woman in front of me trying to soothe her dog. I think the dog knew the cat was there and was annoyed. My cat, of course, could not have cared less that there was a dog around
. If your cat(s) is (are) skittish around other animals, you may want to trade seats with someone.