The FAA requires that your pet be transported in a container. The container must be small enough to be stored under the seat in front of you. Pet containers must not block a fellow passenger's path to the main aisle of the aircraft. Pet containers must comply with FAA carry-on baggage rules as set forth in FAA rules: 14 CFR part 121, section 121.589.
All pet containers must be properly stowed under the seat before all passenger entry ways to the aircraft are closed. The aircraft may not leave the passenger gate until this requirement is met to the satisfaction of the airline cabin crew.
Your pet container must remain under the seat while the aircraft is taxiing to the runway and taking off. The same requirement must be met during landing and taxi procedures to an exit gate.
Passengers with pets transported in the aircraft cabin must follow flight attendant instructions with regard to properly stowing your pet.
You must follow all FAA regulations when traveling with a pet on airlines that permit pets in the cabin. Most airlines will impose added requirements for travel with pets to ensure the comfort of your fellow passengers. The airline may have a limited list of pets that are eligible for cabin transport. Some airlines will place limits on the total number of pets that can be in the passenger cabin for a given flight. The number of pets a single passenger may have in the cabin may be limited by the airline. Airlines may require that your pet be harmless and free of offensive odors. Most airlines will require that your pet remain in the container for the duration of the flight. Airlines may require you to produce a recent health certificate for your pet.
