To ensure a smooth and efficient passenger movement onboard the aircraft, spirit airlines boarding groups employs a group-based boarding method. Spirit boards passengers in groups, and each group is summoned to board in turn, unlike airlines that have assigned seats. Passengers who need special assistance usually make up the first category, followed by families with children under the age of fifteen. Following these groups, travelers are contacted according to the boarding group they were assigned, as shown on their boarding pass. Usually, these groups are numbered, with the smaller numbers boarding first. While others board in a seamless and orderly manner, the system is made to guarantee that passengers with particular needs—such as families and those in need of assistance—are given priority.