I just got approval to take O to my cousin's wedding in September. We will be flying across the country. Both legs have one layover but it is a very short flight and then a very long flight (and vice versa on the way back). I've never flown with kids so I want all of the advice. Packing advice, apps for the flight (I'm ordering a Kindle Fire ASAP), toy/entertainment/snack ideas, etc.

Thanks!