It was revealed at the end when James got his memories back was that he a Britannian soldier who was given the memories of Zero by Charles.
Originally, when he was young, he wanted to become an actor, which is why he felt drawn to movies. But his father didn't approve, so he joined the military. He served as a pilot until being summoned before the Emperor and having his memory altered.
The plan was to use him to find C.C., and the head of the Brighton development was under orders from Bismarck Waldstein to let him steal the Brighton to get back to Area 11 so they could use him to track down C.C.
Della, the test pilot, wasn't in on the plan, and shot him down when James started to feel hesitation with fighting and let himself be shot down. Della and James seemed to be falling in love as then went on dates to see movies together. Della and James were unaware that they fought one another, so she has no idea that James is dead when she heads to their planned meeting place at the end of the chapter.