Not sure if anyone mentioned this, but make sure to pack an extra shirt/top/layering piece for yourself... in case you get a mega spit-up or throw up on you. I stumbled across that tip while reading through one of the BB posts, and I'm glad I did.... my normally non-spitty-uppy DD lost half her lunch, and most of a six ounce bottle, mid-flight... and it was all over me. Luckily, I packed an extra t-shirt for myself in her diaper bag!
Oh, and another tip (really more like a joke, lol!): a friend told me to offer to buy a drink for all the people seated immediately around me... kinda' broke the ice, that "yep, I have a baby on this flight, but get over it people... cheers!" (I did not actually buy anyone a drink, but I did joke about it on one of our first flights... it made some of the other passengers laugh!)
DD born 9/1/09... she's tiny but mighty!