I have no specific context here, but in case it's not obvious, I think you have to read the exchange in the context of British, and I guess RAF, indirectness and understatement.
I'm guessing the air marshal means "what the hell were you thinking"; Holden is agreeing, indicating that he has learned his lesson and acknowledges the error; and the air marshal is then graciously moving on.
I'm guessing the air marshal means "what the hell were you thinking"; Holden is agreeing, indicating that he has learned his lesson and acknowledges the error; and the air marshal is then graciously moving on.