2. I do not know whether the pilots have their own air supply but everyone else is clearly at risk from recycled air with one passenger coughing flu virus out at incredible speed.
Sorry, kpd, but I can't let that one go. You are at no more risk of infection spread in an aircraft than on a bus or train, actually, you are probably at less risk because of the quality of the filters and the controlled air flow within the cabin. Obviously if you're the poor sod sitting next to someone unfit to fly the filters are not going to help, but they wouldn't in a theatre or on the tube either.
FWIW I had the jab yesterday and a (very) sore arm is my only side effect. Last year I had it straight after coming back from a trip (tired and cold-y) and promptly went down with a cold. My company warns you not to have it if you're already ill, but I thought I knew better. Learnt my lesson for this year.