problem with motion sickness? - are you going on a very small commuter plane? or are your children prone to that in a car?
if not, I think you'll be fine.
earpain - what are the ages of your kids? I personally give my kids a decongestant type med before we board the plane to avoid ear pain before they fly & I aways take ibuprofen.
Pack a water bottle for each of them & some snacks in their backpacks. Nothing worse than a thirsty or hungry traveler!
Add some surprises along with some familiar toys. Books, cards, coloring, magna doodle, sm dolls & cars, sm
lego set to put together, crossword puzzles, sm playdoh...........
One of my children used to be terrified to look out of the airplane window - but usually kids like to sit at the window seat. If you only have one window seat assigned, let each one take a turn so they can look out.
Take their photo on the plane! also mention to the stewardess when you board this is their first flight - (they usually offer little pilot wings to the kids - makes them feel so special).
If you are flying at naptime, or bedtime, make sure you get blanket/pillow from stewardess. I am always chilly on planes...
Depending on your flight there might be a movie offered. Some airlines ask for $ to watch the movie (!) but if it is one appropriate it is worth the extra sm charge I think.
relax & enjoy your trip!