You can consider these Lamaze cloth books: http://www.cutie-de-palace.com/index.php?route=product/product&product_id=190 For example, Peek-a-boo forest has a plush owl on the cover that is crinkly and would be interesting to your baby. Each page has a fun peek-a-boo flap so that baby could "explore" those. Reading to your baby could help keep him/her entertained as well. :)
I brought his mobile "steering wheel" to play in the flight as well as attached onto the stroller. Also, I bought a new toy that has sound. New toy is because, he wont be bored and will be interested to explore how to play the toy. Mainly, I gave him toys with sounds or bright coloured storbooks to capture his attention.