What's the fuss with the optical drive?
Just plug it in
and watch your movie on the plane if you like. You were carrying a DVD case anyway. So, you wouldn't mind to carry Apple's portable external optical drive, would you?!
I love the tilted keyboard of the Macbook air. Wish it would make it to the new Macbook pro. For that reason alone I want Apple to leave the optical drive out. Other (more obvious) reasons are more storage capacity and longer battery life.