The comment I made yesterday appears on my record setting page, but it refers to Ahmad Hussain's record video for his record for the one minute martial arts straight punches. Please view it as well as mine. He is a very focused puncher.
Yes, it is more than a flick of the wrist. But it is not a part of the punch to lock an arm fully out. That would allow an opponent the opportunity to break the arm. You never lock an arm out. The title straight punch refers to how it is delivered, not to the arm being straight. The punch comes in straight. Toward the end I see some circular movements that make it then more of a Wing Chun strike than a straight punch. Wing Chun is quicker by nature of the punch. Circular movements relax joints and the relaxation adds to speed.