Hi @snow, and anyone else reading this, if you are facing a trip that absolutely requires flying, I think the thing to do may be to go right "upstairs" here to @fleemoore and download that TSA card.
I can't say it will be an iron-clad guarantee that you won't ever be stopped if you're wearing a diaper while going through a checkpoint, but at least it's a "tool" that you can show if you feel that you may be challenged by someone like the TSA. Just have the card handy and, as I like to say, expect the worst but hope for the best!!
I think it's better than nothing!
But for virtually all of us, a diaper or other protective undergarment is necessary for those times when we have our inadvertent losses of control.
And also right "upstairs," I mentioned that people with all sorts of disabilities and physical conditions do travel through all airports literally every day of the year so someone in a diaper shouldn't raise any eyebrows while passing through the checkpoint. And if it does still, after all this time, does raise TSA eyebrows, then shame on them!!!
If that prospect is still intimidating, then we all remember the slogan to "go
Greyhound and leave the driving to us!!!"