Let's Fly

Let's Fly is the first extended play (EP) released by B1A4 under WM Entertainment on April 21, 2011. Composers featured in this EP include Lee Sang-h, Im Sanghyuk (Beast’s main songwriter), and Jeon Dawoon (K.Will’s main songwriter).

Additionally Jinyoung was partially involved in songwriting while all raps were written by Baro.

Background
A music video teaser for B1A4's promotional single "O.K" was uploaded on April 19. The full music video, as well as their debut EP, Let's Fly, was released on April 21. The group made their debut performance on the April 23 episode of Munhwa Broadcasting Corporation's (MBC) Show! Music Core.

They had their subsequent debut stages on Mnet's M! Countdown, Korean Broadcasting System's (KBS) Music Bank, and Seoul Broadcasting System's (SBS) The Music Trend on April 28, April 29, and May 1, respectively. B1A4 began promoting Only Learned the Bad Things on June 18, 2011.

The group, alongside Block B, starred on SBS MTV's reality show Match Up. It began to air on June 22. The music video for the second promotional single "Only Learned the Bad Things" was aired on the first episode.