"Fly High Project #2 'Rooftop" (Fly High Project #2 '옥탑방') is the second digital single by N.Flying. It was released on January 2, 2019 as the second part of their year-long "Fly High Project". The group returned as a four-member band following Kwon Kwang Jin's departure in December 2018.
The song "Rooftop" was a sleeper hit a month following its release. It slowly climbed on the Korean online music charts, eventually topping on several charts including Melon & Bugs. N.Flying earning their first music show win on March 5 on The Show.