After many years of flying frequently without mishap, I was recently as sick as a dog on a flight from LHR to EWR (777, I think). The weather was appalling, and we were forced to circle New York for 45 minutes. The plane was being blown all over the place, with frequent sudden drops and rises, and eventually I could hold it in no longer and filled almost the whole sickbag. (The food had been good and plentiful, and there was a lot to come up). Then the woman next to me began to gag, and someone behind was definitely sick. I think it travelled through the plane like a Mexican wave.