Please share your best tips for flying with a "lap child"

[kristennn]

We're flying with a lap baby (that will be 9 months) next week!
We flew with my daughter when she was just a week short of 2 and bougth a half price seat for er and brought her car seat too. We put the car seat beteen my husband and I and man - that car seat took up a lot more room than a regular person would take up - made it difficult to pass her back and forth between the two of us - and she didn't sit in ot at all - but instead insisted on being on our laps the whole time.
With our current baby- she doesn't usualy sleep in her car seat and I am sure she wouldn't lay on her back in it if we were sitting right next to her so we're not even going to try.
I do plan to nurse her at take off and landing and anytime she gets fussy. We'll make sure she has a clean diaper on before take off and unless she poops we'll just change it when we get there. (2.5 hour flight)
We're flying Southwest - and we also have a 6 year old - and since I cannot imagine making my 6 year old sit away from a parent we paid for early boarding so that all 4 of us can sit together.
I am sure it won't be the most comfortable 2.5 hours of our lives but we'll get through it.