J.J.
First off, don't even think about worriying about anyone who may give dirty looks because your 8 month old needs to eat. I'm sure they all eat in public :)
If you think you may be traveling more while your child is young, I really recommend getting a Sit and Stroll. Yes, it is a bit pricey, but worth its weight in gold for not having to haul around a stroller and a car seat. Plus if your little one falls asleep, you don't have to disturb them to switch from car seat to stroller. I got one for a recent trip with my 13 month old and loved it! It does strap right onto a car without the need for a base too. Let me know if you want more details or have questions on it.
As far as the flight, you are free to take baby food on, but because the conatiners are over the 3oz limit, you do have to declare them at security. Just put them in the quart size bag and show them to the guards. I took through both Stage 2 and 3 jars with no problems.
We didn't have any issues with air pressure hurting our sons ears, but if you think you may have problems your pedi can prescribe ear drops that will stop her ears hurting in the plane. I know people who wouldn't travel without them.
Remember a couple of fun toys, and don't feel bad if you have to get up and walk up and down the aisle with her. I had to do that and the flight attendants were awesome about letting us hang out in the galley with them. They even took him and played for a few minutes. It really saved us when my son got bored!
Good luck. Have fun. I love California!