I've been traveling a long time now and I have used all of these tips... except the one with the air vent. I've found that just asking politely but loud enough for people around you to hear, "Excuse me, can you put your seat up while we eat?" always works. A person confronted in public with being an obvious jerk and no way to leave for an extended period of time will (so far) choose not to be a jerk. But if that ever fails... it is a wonderful tip!