 An expansion plan announced in September 2015 called for an extension of the check-in area, an expansion of concourses D and E into a 1.3 km long concourse, a new passenger amenity area in the D/E complex with lounges, shops and restaurants.As part of this expansion plan, the Doha Metro was extended to the airport with the opening of the red line airport branch in December 2019.In 2016, the airport was named the 50th busiest airport in the world by passenger traffic, serving 37,283,987 passengers, a 20.2% increase from 2015.