US Airways has the following policies on pet-travel:
Pets are allowed as carry-on for travel throughout the continental US. Check their website for information on travel outside of the US.
Fees: $125 each way.
– The in-cabin weight limit is 20 pounds including the kennel that must be able to fit under the seat.
– Only 3 pets can be on board at one time, so advance reservations are advised.
– 1 small domestic dog, cat or bird per passenger.
For complete guidelines, check their site at: US Airways