Controller gave him: "Cleared direct DAWNN, fly planned route."
FDX2707 responded: "OK, we'll make a left turn to 175, we'll go to Atlanta."
DAWNN is the first intersection on the DAWNN departure. So, the pilot should have read back "Cleared direct DAWNN" as he was never given clearance to go direct ATL. Depature controller didn't pick up on that.