Continental recently raised its in-cabin pet fee to $125 each way, giving it one of the highest such fees in the industry. The change took effect July 15, and represented a $25 hike over the previous (and more typical) $100 fee.
Now, some might say this fee is insignificant because it affects such a small percentage of the flying public. Heck, I'll likely never pay this fee even though I'm a pet owner myself (my dog is too big to fly in the cabin). But what this fee does illustrate is that airlines these days are raising or adding fees for every conceivable aspect of flying, and while certain charges may affect only a scant few passengers (I'm sure many of you chuckled at Frontier's $100 antler fee, but I guarantee there's a hunter somewhere who didn't), the airlines will take all the extra cash they can get.
So who has the cheapest in-cabin pet fee? That would be AirTran, at $69 each way. Northwest is next at $80 each way, and Spirit charges $85. The remaining major airlines come in at $100, except United, which also charges $125 each way. Southwest doesn't allow pets in its cabins at all and, oddly enough, neither does Frontier (maybe you can tie antlers to your dog, a la the Grinch? Nah.)
If you can't keep up with all these fees, check out our handy Ultimate Guide to Airline Fees, which is updated regularly.