Ok, I've paid for Romeo's tickets before and found that they give you absolutely no documentation or any "plane ticket" for your pet on the plane with you (you're allowed to take a pet on board under 10lbs). In fact, you don't really have to say anything to them after paying for the ticket. So, I got tired of paying $100 each way and tried sneaking him on as a few of my friends had done with their tiny pooches..
When you pass through security, u take the dog out of the carrier and then someone will pass him over with the wand to make sure he has no explosives or weapons in him.. hehe. Then, about 30 min before takeoff, I give him a sedative to keep him calm. Once I'm on the plane I make sure to get a blanket or bring one of my own, pull him out of the carrier and put him on my lap under the blanket (if he can handle sitting under the chair in front of you good, but mine yips if he can't feel me). Romeo usually sleeps the whole plane ride and if he wakes up I make sure to have treats easily accessible to keep him occupied. Honestly, once I'm in the air I don't worry, they're not going to turn the plane around for a 4lb yorkie. Plus, a flight attendant caught him once and he checked and found Romeo wasnt listed on the flight. When he told me I just acted horrified they hadn't listed him because I had paid $100 for him ;) ..
It's a little stressful but worth saving $200!

I really like that guess carrier! Where did you find it? :D

Thank you! I bought it at the Guess store, they used to be on their on-line site as well, but now I can't find them there, I have also seen some on ebay.

This is all great info thanks so much. I need some answers to this as well. Does anybody have any suggestions for puppy carriers? My baby is 12 weeks old and I have been transporting her in the crate she sleeps in at night and durning the day. But it is a little big and bulky. Would you recomend just getting a tote for her to grow into?
Thanks.