I think everyone from, every walk of life and profession can empathise with this situation.
Now while much is made of turning a negative situation into a positive or not creating barriers I think we must all ask ourselves when this will actually cease from being a gentle dig in the ribs to becoming a complete pain in the ar*e.
No text book will provide the answer as the answer is within you. Does the remark cause you offence this angers/infurites you in which caase it will inevitably be at the back of your mind for the rest of the flight or can you handle such throw away remarks without causing any build of bad feeling that will affect the flight.
How would I handle it? If it was of the 'throw away' type that didn't bother me eg I would acknowledge him with something light hearted. Eg in response to "i've got to fly with you twice next month" I might respond "You mean I've got to fly with you again? Remind me to go sick."
HOwever if I felt it sufficiently derogatory I would cut to the chase and explicitly state "I do not find your remarks or attitude condusive to a professional working environment. Whil