Hi, I just flew Cross County with a 6-month Baby Girl.  I checked all the websites, FAA, the airline before my flight and they didn't list any of these tips and info below.  Here are some tips and what they don't tell you.

1) Car Seat and Base:  It doesn't not cost extra for them, Its FREE (most airlines only allow one check bag).  I took with me a Large Yard Garbage Bag.  I went to the check in counter (assited or not) and with the babbage guy there I hooked the car seat to the base, clipped the hooks together over it, clipped the tilt thing all the way in (yours may not have this feature, but it helps it not break) and put in thick yard garbage bag and noted the top. I put it in the garbage bag in front of the guy so that I didn't have to rip it open. Also you know how luggage looks after a flight.  The base could come off the car seat and at least they are together and put luggage tags on both and the bag.

2) Stroller: You can use the strooler up untill you are getting on the plane.  They put them right in front of the plane in special storage area for wheel chairs and strollers.  When the plane lands you get it right back.  They use the wand and security thing.  I carried my daughter in the front pack thing, she is 16 ibs.  The web site said nothing about it.  ITS FREE. 

3) Security: When you get to the security line make sure the security guys see you.  You get to cut to the front of the line.  And they help you take your shoes off.  They help pull things out of your bag to declare. You don't have to let them handle your baby and strip them naked.

3a) Bringing formula:  You can bring a can of formula and empty bottles (I bought bottled water at the gate area).  You can put your water in them.  I didn't because of wieght.  I left the can unopened.  You just have to pull it out and declare it at security. 

3b) Bring babys Birth certifacite: They didn't aske me for it, but the airline said to bring it anyway.

3c) Put your 1-quart bag of liquids on the top of diaper bag: I got travel size Purell (a must), wipe holder, lotion, and diaper rash onitment.  Remember you are carrying this bag (if not in stroller).

4) Fly at Night if you can:  I got on the plan at 9pm and she sleep the whole time. The airline does try and keep the seat next to open.

5) Feed while going up and down to pop ears:  Try and feed while your going up and down and that helps pop their ears.

6) Bring your babys favorite toy: I also had on some costume bracelets for my baby to play with.  it help with her sitting on my lap during take off and landing when she was awake.  my ares where around her and she pulled and grabbed them.  you don't have to worry about losing them, digging in the bottom of the diaper bag, or leaving them on the plane.  I also had her in a baby front pack holder.  try beaded big ones with dangly things and shiny things.

Have a safe flight!!