DJ is a human F-22 pilot, who took part in an attack on Megatron and some of his troops. He has a picture of his gal, who he'll no doubt marry next week since he's clearly just two days away from retirement. And probably about to be a Dad for the first time too.
IDW comic continuity
According to his buddy, Andy, DJ made sure to rally the troops before they were scrambled to clean the clocks of some giant robot terrorists. Before taking off, he made sure to steal a quick glimpse at the photo of his sweetheart he carried. Things didn't go as well as he'd hoped, as they were set upon by three unusually powerful F-15s and a pair of giant animals! He got a lock on a black F-15, when it suddenly changed forms, becoming a robot and shooting him out of the air. In an attempt to make the best of a horrendous situation, he kissed the picture of his girl goodbye and aimed his dying jet at the largest robot... who calmly and easily swatted it like a fly.