In 2026, budget airlines continue to dominate the U.S. aviation market by offering competitive fares that keep travel affordable for millions of passengers. This comprehensive analysis ranks the 10 cheapest airlines based on average domestic fare data collected throughout 2026. These carriers have maintained their commitment to low-cost travel through operational efficiency, strategic route planning, and competitive pricing models. Whether you’re planning a cross-country trip or a short regional flight, this guide will help you identify the most economical airline options available today.