I don't know who you fly with but people I know and myself have always been able to during the flight. Just not on landing and take off, (which is only a few minutes)or moderate/increasing turbulence. Otherwise we'd take it off and walk to the back, then come back and put seatbelt back on. I've always thought this was standard and always been able to. Whether this isn't meant to happen I have no clue, but never been stopped or told I can't and haven't seen anyone else on the plane who did so, get similar instructions.
My talk about periods was about the impact on attendance (one of the main reasons for absence, girls are reporting and other resources are showing) and some of the further issues it's causing. The issues around some now automatically taking their whole period off (not counting those with more severe symptoms btw, many say its due to fear over not being able to go to the toliet or having to announce that to their teacher/the whole class - links back to issues around boys bullying them with misogynistic jokes many centered around periods), the issues around leaking through at school and the issues with girls doing sports around (haven't touched on this lots but it is another key part of research findings). Less girls doing P.E and not doing it at all on their period (partly due to pain but also things like cultural reasons of shame, but even those who don't have those cultural backgrounds being scared of leaking due to badly designed kits, not made for girls, feeling embarrassed by it and the like). It wasn't in the post you referenced but a couple of posts on a 2 or 3 pages back I think, where I linked the studies and research and then my wider points on periods were the very first post I did on the 1st page.
Periods do still occur on a bus yes, and that is a unique scenario, which is very far and few between. And on the bus some girls will still leak through, and will need to go. It doesn't go away on the bus, so yes they should wait if they feel like they can, but if not I'd rather stop. If rather teach our girls that the attitude of girls are constantly over dramatic about pain or discomfort on their period isn't okay. The attitude that they shouldn't be given empathy and more support isn't okay. The attitude that they should such up heavy bleeding and bleeding through because a bunch of kids will now want to go as well and that's annoying or will waste time - so they then can't go, if they really need to, isn't okay.
I have bled through on a coach (not with school) but on the one or 2 times I was on my period and we had a trip, I was so petrified over it happening again. Bear in mind, I used 2 different products at once as well. I often bleed through and have since my periods started 7 layers (as in through to my mattress). I didn't say anything for years because I thought it was normal, and everyone looked at periods as disgusting or weird so I didn't want them to think that of me. Then even when I did start getting investigations it took ages for a diagnosis, and it was trial and error with meds etc, and they took time to work (as I mentioned in my 1st post, gyne issues only just start to appear during teens and unlike other medical issues are more likely to have have had medical intervention first, or not need it, but just take a while to settle). I was lucky that by Y11, I had a great deputy head/english teacher who sorted it all out for me, even without medical evidence and made it more manageable at school through lots of different systems and spread period passes for every year and in my new 6th form, they gave me all the accommodations I could possibly need.
That's why more schools than ever do have period passes and cards, it's becoming much more common, as it should be. Also periods are every 4 weeks, some girls will be on their period, but it's not exactly all of them. We don't make policy about the day to day, regular processes based on occasional situations which aren't ideal nor should they be the norm. Holding once or a few times rarely and spread apart, is very different from having to do that regularly, which causes issues like UTIs and even if not that bladder issues.
I have seen the novelty of someone going so now somebody else wants to. I've also seen kids leak through, blood everywhere and I've done that myself, I've seen kids get sicker and way worse, as they weren't allowed to go. So we don't stop it because x may need the toliet and then y might. As long as x genuinely needs the toliet.
I'd rather wait an extra 10-15 minutes than not let a kid who needs to go, go to the toliet and I think lots of staff would as well. Unless all the buses have to then stop and everyone goes, I don't see how it adds on extra hour, whenever I've done that it was at the longest, around 10-15 people, mainly girls and took 20 minutes. We'd go in one at a time, and often that did take the novelty of the fun girl time in a toliet, and some wouldn't go. I also never said that children should have to go immediately in a lesson (other than medical issues and periods or an emergency), kids can wait for 5 minutes if there's a really important bit or if after that they'll pack up, so can go then. I am against the 100% bans (other than medical evidence/pass), and I'm against overly restricted toliet use. I don't want any kid to get hurt, but I also don't want them to wet themselves or bleed through.
My responses weren't funny, what I was saying is that, you've mainly focused on this bus example as justification for the polices, which are applied in a different environment. The issues I referenced as the maim problems with toliet policies are real and as you'll find contained reference of the research and work from lots of important bodies on the issue.
When I would say tha that your bus situation, whilst true, is an occasional event, and lasts for not that long at a time (depending on the trip). So I'm saying that your example is the least important issue of all the issues I and many other PP have talked about which result of these toliet policies being too arbitrary.
Even with supervision, some of the valid problems mentioned by others, still happen. They still may beat someone up or, vape etc, evem when teachers are there and teachers try to stop them. Thats why rather than toliet policies which are often band aids to the issue and just push them to different areas, rather than working on them in constructive ways. I often need the toliet when I'm out. I've found across lots of areas there's always plenty of toliets available which aren't that far and in an emergency I have gone into places which only have staff toliets but they let me use it. Otherwise I find lots of public toliets available or in shops or something. So that's how I cope.