What Are Some Tips For Bringing A Baby On A Plane?

This weekend I'll be bringing my daughters on their first flight and not sure what to do. I'm not worried about my five year old, but I need some tips for my almost two year old. 

We'll be traveling to California for some family fun labor day weekend, but i'm not sure how my daughters will handle their first flight. I'll be bringing the portable DVD player for Zoey (my five year), but Belladora (19 months) I'm a little worried about.

My wife will be with too, but I still feel it might be a struggle. Any tips for keeping an almost two year old calm on a plane. I don't want to be that family that disturbs the other passengers with our crying baby.

The flight is three hours and I need help. I read some tips online about going to the airport early and have them run around or bring a lot of snacks on the plane. Let me know if you have any good tips in the comments below. Thanks in advance!