Market Structures. Explain the most important characteristic in perfect competition, monopolistic competition, oligopoly, and monopolies and relate the characteristic to how these firms can make profits in the short run. In your analysis, make sure to relate an example for each of the market structures listed and how it relates to the particular characteristics. 

Barriers to Entry. Analyze the major barriers for entry and exit into the airline industry. Explain how each barrier can foster either monopoly or oligopoly. What barriers, if any, do you feel give rise to monopoly that will allow the government to become involved to protect consumers?