Wow, when I travel with my dog, most people at the end of the flight--when I haul him out from under the seat and start talking to him--are like "holy cow, there was a dog on board this whole time?" It helps that he's black and the bag is black---he gets to go incognito.
The only time he ever got vocal was when I was standing in a line at the AA desk to check him in that wasn't moving. After about 20 minutes of us waiting out one problem passenger, he let out this moan/sigh I had never heard before. All eyes were on me, and one man said "Miss, are you all right?" Everyone had a good laugh when I told 'em it was the dog (channelling my frustration, no doubt).
But I never take him out. I can't expect everyone to be dog fans, people have allergies, etc. Too bad people feel entitled to foist their pets on others. Kinda like parents who foist their kids on others!
UA is $85, AA is $80 each way the last time I flew with the beastie. So CO is a bit higher---for now. It's only a matter of time before the other airlines increase theirs, too.