Source: Based on data from Air Transport World and RITA/BTS.
One of the main outcome of deregulation was the consolidation of airlines and a gain of market share. Two of the four largest airlines in the United States before deregulation, Eastern and TWA, went bankrupt. Pan Am was another carrier that failed to survive the depredations of deregulation. Overall, however, the large hub-and-spoke carriers gained market share nationally until the rise of the low-cost carriers in the late 1990s. By 2005, Southwest Airlines had already 7% of the market (based on revenue passenger miles), a share that climbed to 15.1% in 2012 and 20.4% in 2018. Only three of the legacy carriers remained with a significant market share (more than 10%); United, American Airlines and Delta.