LaGuardia Airport’s new concourse is open. Nearly a dozen gates opened Saturday in Terminal B as part of the airport’s plan to renovate the dated facility. The modernized concourse offers additional dining and shopping options for travelers. … The improvements are part of an $8 billion blueprint to revamp LaGuardia, including an addition of 2.7 million square feet to make six new concourses, 72 gates and two new arrival and departure halls.