The Justice Department has agreed that the merger between United Airlines and Continental would not violate laws designed to ensure the market remains competitive, since many of the airlines routes are complementary.

The Justice Department agreed to the deal after Continental agreed to allow Southwest Airlines to use its hub in Newark, New Jersey.

Continental accounts for around 70% of the passengers that pass through Newark and when merged United-Continental will operate 442 daily roundtrip flights from the airport.

By leasing takeoff and landing permission to Southwest, the smaller airline will be able to operate 18 flights per day by 2011. The airline is currently unable to operate any flights out of Newark because of Continental’s dominance.

Shareholders in the two companies are planning to vote on the merge by September 17th and the deal is expected to be finalized by October 1st.