Kimi to Kami Hiko–ki to.(2008)

This is a 4-koma featuring the high school kid Kei, and his childhood friend Rin, who loves paper airplanes. Kei seems to like Rin, though he's somewhat oblivious to his own feelings. With the addition of Rin's classmate Ryuusuke, who shares her love of paper airplanes, and another new character, Aoi, Kei's emotions become more and more complicated. Apparently feelings, like paper airplanes, don't fly straight.