This paper suggests that airline deregulation has profoundly affected the structure of firms that operate airline networks by affecting the contractual conditions under which airlines purchase labor inputs, by removing constraints on the extent and nature of the firm’s route network and by changing the competitive environment in which airline firms operate. Where a stable uniform firm structure existed under regulation, airline networks now are organized with a variety of firm structures and individual networks have changed as particular conditions have changed over time.

 Regulation and the Nature of the Firm: the Case of U.S. Regional Airlines