G.T.
Hi T., my daughter is now 5 months old and her first plane ride was at three months. They sell carseat totes that can be checked plane side. We also had a front carrier and umbrella stroller. Seems like a lot but we didn't know what to expect. Turns out one way the stroller was best on the way back the carrier was best. If you decided against the carrier it fits nicely in the carring bag with the car seat, which by the way comes with straps to wear as a back back & also has rollers for pulling. Baby items are free and don't count against you for carry-on or checked items. Had no problem taking my pump & expressed milk through security. Their quiet as up tight now (travel was this past July 2008). As for diaper changes our longest flight was 2 hrs so I changed her before and after we landed. If they can make it throught the night, a plane ride should be a piece of cake. A blowout is different, head for the restrooms. :-) Keep some hand sanitizer handi too.
Hope this helped. Me, I'm a fist time Mom too!