I had to do it last year with a 1 month old and a 1.5 year old to go to my brothers wedding. It sucks.
First, check in outside. Airlines do not charge extra for carseats, and it stinks getting them in. You will need them.
Separate all the liquids from everything else for . GO TO A WOMAN and let them go through the baby stuff. Bottles, pump, etc. Seems to work out better.
They will check a stroller at the plane. Do this if possible. It was very hard to keep 2 kids together without strapping them down.
Load the plane early. Get all the stuff you need, including a bottle for takeoff, diapers, food, etc. We did not have any problems with the kids ears on takeoff/landing, but they were eating and that seemed to help with pressure.
Get plenty of sleep before you go. I told my wife I am not taking a plane with the kids until they are 10.