I Flew from plotland Oregon to Texas and from there to Brittin. IT was around 15hours of flying. i have sleep incontinence due to a issue my doc can't seem to figure out. I was able to stay awake and dry from Portland to Texas but not from Texas to Brittin.
My recommendation is this.
1.Game plane and airport bathrooms.
First keep all your family's incontinence supplies in one bag and keep it as a carry on. Your kids don't sound disabled so they should be able to change in and out of goodnights pull ups in the ordinary bathroom stall. If their afraid of publicly disposing their pullups as i would be too i would recommend keep some small garbage bags in your carry on and store the used incontinent products in there until you can get through the line for the family rest room where you can dispose of them privity. That's what i did and it worked out and no one was the wiser. Oh, i also almost forgot. Get changed before getting on the plane so you dont have to wait an hour after takeoff to use the rest room. dont know why but it took forever for that unbuckle light to turn off lol.
2. airplane bathrooms.
When i was on my way to Brittin i ended up leaking late in the morning. I admittedly had too much to drink on the flight and would end up paying the price. Note, limit fluid intake! The more you drink the more you pee, its just science. I would recommend you wake up your kids and have them change when the majority of the cabin is asleep. Remember to keep the diaper bag on you so you can hand it of to them when they go to change. Now when i woke up and noticed i was wet where i shouldn't have been wet i knew i had to go change before landing or it would be a sad day for myself. i grabed my diaper bag and went to the bathroom and changed my self. when you're in there you'll see a TINY little square garbage can built into the skink countertop. I was able to fit a soaked M size North Shore Mega Max in it but i had to feed it in stretched out and unfolded cuz the hole was small. be sure to let your kids know that so they dont panic like i did. After i got changed i couldn't find the garbage can in the bathroom and had to put my diaper in a garbage bag and put it in my carry on. Luckly my mom told me there was a garbage can in there and described what it looked like, and then told me to just shove it in there lol. Nerv's can make the obvious not so obvious so you might want to go over this with your kids, so they have an idea of what to do as well.
But yea after all that i had a good flight. the trip was bad tho. i ended up running out of diapers in Vienna Austria and had to go the pharmacy and get some. Lucky a cute girl my age was there and spoke English and was able to help me. they only had attends which was a bumber. But the German brand attends are at least a little better than the American ones. Regardless after that i had to regulate my fluid intake before bed but even then, the attends leaked on me so my mom made me tell the hotel staff i may have ruined their bed and to ask how much it would cost to cover damages... thk mom.... good memories lol jk. Overall, just be sure you bring enough for your trip and learn from my experience, and you should be fine
best of luck!