I typically am not a day wearer but about 6 months ago I woke rather quickly from a nap on a long flight. I was on the edge and caught it just in time. I had my PUL plastic underpants in my carrying on bag but do not use them until I go to sleep at the hotel. Being on the edge I got up and pulled them out of my bag (had it in a plastic bag) and changed in the airplane lavatory (on an airplane it is a lavatory, anywhere else it is a bathroom - go figure).
I used the toilet but after going to my seat and being a bit more secured I wondered what would have unfolded if I had not woke up in time and visibly had an accident. I then decided wearing for long flights made perfect sense. I recently flew on a 6 hour flight but this time had stocked up with Depends Pull-Up Full Briefs for men (yes not the best for SAP but good enough for my situation). So going through security I have 5 briefs and my PUL in the bag. The TSA guy says something about the machine cutting the picture off and wants to run the bag through again. He runs it again and before he provided a response I offered to have him manually check my bag. I have seen them run their hands over my protective undergear before and they have NEVER made a scene about it; in fact, they just keep going on and typically might pull my small coin purse up a bit to look at it. I then go to the airport bathroom by the gate and change into my brief, pull my regular underwear over that, and pull my PUL over that. Yes a bit bulky but not that revealing.
So by 5 hours into the flight I have the urge to go. At this point I am committed so I let go a bit and fall back to sleep. About another hour and I wake up having to go again so I let go a bit more. By the time we land and walk through the airport I really have to go but decided to test it some more and let go again (about 10 seconds each time). I decided to stop by for some lunch and use the bathroom and noticed my brief still had a ways to go so I just let loose and head back to my table and finish lunch.
As I checked into my room I decided to take another nap and placed my plastic mattress cover on the bed. Instead of changing I just hopped into bed and fell asleep fully soaked for about two hours. Waking up and being soaked but still having no leakage was the greatest feeling of security! I took a shower and decided to change into another brief and my PUL and went to dinner. I watched TV after that for about 2 hours letting go a bit each time for about 10 - 15 seconds. The next morning no leakage but fully soaked I came to the conclusion that "letting go" for only 10 - 15 seconds several times an hour is better to lower the potential for any leakage than letting it all go at once. Not so mind-boggling but sometimes logic does not work the way you think. I plan to do this on my next long flight again as the comfort / security was incredible and I can take a nap with no fear of not catching it!