My son was six and suffered from unexpected air sickness. The first flight, he started screaming into his headset as I was on finals - his stomach hurt badly and he couldn't believe that his mummy wasn't even *trying* to make it better. Luckily my other half hit the mute button so that I could use the radio - it's worth bearing in mind that despite warnings, under pressure you might find the child forgets what he's been told.
Obviously we had even more long talks about what was happening and remaining silent even when sick as a dog. It's odd as he quite happily sits in the backseat and reads during long country drives, but I've learned to give him a Quells before putting him in the PA32.
