It's easy and straightforward for travelers to fly with Frontier Airlines PHX Terminal With its quick check-in procedure, state-of-the-art security procedures, and a variety of dining, retail, and seating options, Terminal 3 guarantees travelers flying with this low-cost airline a seamless departure. For passengers flying with Frontier Airlines from Phoenix, Terminal 3 is an excellent option due to its amenities, which offer comfort and convenience at every turn, even though it lacks first-class lounges and other terminal perks.