It's an aot (or snk) survey corps wings of freedom. Basically the aot logo lah. I Guess. Only 11 more days till season 2 comes out!!! (As of 5 April 2016)

The logo was damn hard to draw and it kinda sucks cos I drew it on my leg (I was sitting cross legged on the floor at Parkway Parade). And I was staring at the tiny picture from my tiny phone. Not to mention I'm kind of blind so ya.