Not charter, I know, but I once gave up my weekend off to fly a Navy Sea King display at Southend Air Show. The aircrew party laid on to reward us for our (unpaid) efforts consisted of 1 small hot dog, served in a nightclub, where the beer was priced at about double what we would have paid in a pub. Cheers, Southend Council! I didnt volunteer for any more Airshows after that!