An oligopoly is a market structure in which a few firms dominate. When a market is shared between a few firms, it is said to be highly concentrated. Although only a few firms dominate, it is possible that many small firms may also operate in the market. For example, major airlines like British Airways (BA) and Air France operate their routes with only a few close competitors, but there are also many small airlines catering for the holidaymaker or offering specialist services.