The Allegiant Air pet policy is as follows:
Allegiant welcomes small live animals/pets in the aircraft cabin within the contiguous 48 United States.
Travel to international destinations and U.S. territories, including San Juan, Puerto Rico may not accept all pets.
Domestic dogs and cats only are allowed in the cabin.
Each paid traveler may have only one pet carrier.
The carrier may be no larger than 9”H x 16”W x 19”D.
Allegiant does not transport animals in the cargo bin.
Taking a pet to a foreign country involves preparation and planning far in advance of your departure date. Requirements for pet travel to a foreign country are set by the destination country. If you are you traveling to another country and bringing along your pet you’ll need to meet the animal health requirements of the country you are visiting.
More information on the Allegiant Air pet policy