American Airlines is the fourth largest and US Airways is the 5th largest national airline.(www.antitrustinstitute.org) The combining of the two would take up 70% of the air travel market, which would create a oligopoly. Oligopoly firms are also able to take advantage of economies of scale that reduce production costs and prices. As large firms, they can mass produce at low average cost. Many modern goods--including cars, computers, aircraft, and assorted household products--would be significantly more expensive if produced by a large number of small firms rather than a small number of large firms.
An oligopoly does not efficiently allocate resources. Like any firm with market control, an oligopoly charges a higher price and produces less output than the efficiency benchmark of perfect competition. “Ogliopoly tends to be the worst efficiency offender in the real world, because perfect competition does not exist,