It is difficult to determine the worst airline as different studies and surveys have different results. However, some airlines that have consistently ranked low in customer satisfaction and complaints include Frontier Airlines, Spirit Airlines, and JetBlue Airways. These airlines have received negative feedback for issues such as flight delays, cancellations, poor customer service, and limited amenities. It is important to note that some of these airlines offer lower fares, which may be a priority for some travelers. Ultimately, the choice of airline depends on individual preferences and priorities.