The Spirit boarding zones Zone 1: Gold elite members. Zone 2: Silver elite members, those who have purchased shortcut boarding or carry-on bags and co-branded credit card holders. Zone 3: Passengers sitting at the rear of the plane. Zone 4: Passengers sitting at the front of the plane.

Zone 3 on a boarding pass typically represents a mid-to-late stage in the aircraft boarding sequence, though its exact meaning varies slightly by airline. In the traditional "outside-in" or "back-to-front" boarding models used by many carriers, Zone 3 usually encompasses passengers seated in the middle or rear sections of the Main Cabin (Economy) who do not hold elite frequent flyer status or premium credit cards. For airlines like Delta, Zone 3 often includes passengers in the back of the plane, following the boarding of First Class, Diamond Medallions, Comfort+, and SkyPriority groups. The primary challenge of being in Zone 3 is the limited availability of overhead bin space; by the time this group is called, the bins in the front and middle of the cabin are often full, potentially requiring Zone 3 passengers to gate-check their carry-on bags. It is essentially the "general boarding" phase where the bulk of the passengers enter the aircraft after the priority tiers have settled, signaling that the flight is nearing its departure time.