NEW YORK CITY—Flights on Air Canada, American Airlines, Southwest Airlines or United Airlines, to and from LaGuardia Airport, will come through the new concourse housing 18 new gates. On the western side, the new, $4 billion Terminal B ultimately will have a total of 35 gates. It will replace facilities that opened more than 50 years ago. On Saturday, 11 of the news gates opened for use with 17 more to open in early 2020. The new 250,000 square-foot concourse has 55-foot-high ceilings and floor-to-ceiling windows. The landscaping includes an indoor park with benches, living trees, charging stations, unlimited, high-speed Wi-Fi, a children's play area, restrooms, restaurants and retail shops. The airport is owned by the City of New York and operated by the Port Authority of New York and New Jersey. LaGuardia Gateway Partners is a private consortium that's rebuilding and operating Terminal B. During the multi-phase construction, the airport is remaining fully operational. Older facilities are demolished only after new ones are completed. Governor Andrew M. Cuomo unveiled the redevelopment plan in 2015 and construction began in 2016. When completed, the airport will be 2.7 million square feet, with 72 new gates across six concourses, new arrival and departure halls connected by a central hall, and 13.7 miles of new roadways. Pedestrian bridges will cross over active plane taxi lanes connecting the main departure and arrival halls with the concourses. In February, the new Terminal B parking garage opened with 3,200 spaces including more than 2,400 for personal vehicles. A dedicated section has 50 marked loading areas for car services. The renovations included creating new roadways and overpasses for vehicles accessing the airport. This was designed to improve traffic flow, eliminating 16 traffic lights. In September, the Port Authority began the environmental review for the proposed AirTrain LGA. This will provide a rail link to the airport at Willets Point, from the Long Island Rail Road or MTA 7 subway line. The route creates another transportation option to and from LaGuardia and Midtown Manhattan. On the eastern side of the airport, Delta Air Lines' new $4 billion Terminal C will ultimately contain 37 gates. It will replace the existing Terminals C and D. The new terminal is scheduled to open in 2021. LaGuardia Gateway Partners and Delta are privately financing two-thirds of the redevelopment's cost. The Port Authority is paying for the remaining one-third, largely for overhauling the network of roadways encircling the airport.