Markets can become more contestable through deregulation, tougher competition laws, and new technologies lowering entry costs. Contestable market theory holds that the threat of entry, not just current competitors, keeps prices low and forces firms to act efficiently. For example, the open skies agreement allowed more airlines to compete on transatlantic routes, threatening British Airways' profits from high-fare passengers. While no market is perfectly contestable, the degree of competition/threat of entry is what matters most according to this theory.