Frontier Airlines primarily operated from Terminal 3 at McCarran International Airport in Las Vegas. McCarran International Airport is the primary airport serving Las Vegas and consists of two passenger terminals, Terminal 1 and Terminal 3.

Frontier Airlines, being a low-cost carrier, was commonly located in Terminal 3. The airport's layout was designed in such a way that Terminal 3 primarily served domestic and international low-cost and leisure carriers, while Terminal 1 typically accommodated larger domestic and international airlines.

It's important to note that airport terminal assignments can change due to operational needs, so it's always a good idea to check your flight details and the latest information on the official McCarran International Airport website or with Frontier Airlines closer to your travel date. Additionally, when arriving at the airport, follow the signage and ask airport personnel if you have any doubts about your departure terminal. This will help ensure a smooth and hassle-free experience when flying with Frontier Airlines from Las Vegas.