There are multiple netbook products and depending from what you want. Basically there is nothing in netbook idea which prevents them to pickup iPad market. The only essential differences between netbooks and iPad for now are a keyboard and a slimness/weight. But that depends - Sony (expensive) is pretty slim.
I don't speak about this stuff - iPad and any touchpad devices are not very good in this anywhere - KBD is absent and thats it. And BT KBD doesn't solve a problem - it is a second device and although it can be used, that solution is not good if there is netbook.
Yes, form factor takes place, and it the reason why i spoke about bedtime. But if we exclude a consumption of prepared content (read - look video, read books) then it doesn't win at all in any situation. And if we speak about airplane then looking video is not the best for it, actually device with N900 form factor is better in it's crammed space. (I am not sure about reading - it may be better to have a bigger screen for many people but Kindles are best here)