Justice said late Friday that it has closed its antitrust review of the United-Continental merger because it is satisfied with the carriers' deal to reduce their combined market dominance and increase competition at Newark. Continental currently operates a hub there and has the largest market share in the greater New York air travel market, the USA's largest. In addition to Newark, New York is served by LaGuardia and John F. Kennedy airports. Together United and Continental currently offer 442 daily flights at Newark.