Should we restructure society so that having a private airplane is easier and cheaper, but if you don't have one you'll have serious trouble in daily life?

No

Is this some culture or region or climate related thing? I’ve never heard of BO brought up as a reason to avoid public transport or flying commercial in northern parts of Europe. Nor have I experienced any olfactory disturbance, apart from the occasional young man or woman going a tad overboard with perfume on the weekends.

Of course they wouldn't, owning and operating a plane is -incredibly- inconvenient. That's what we are discussing, tradeoffs of convenience and discomfort, you can't just completely ignore one reality to criticise the other (admiting some hypocrisy here since that ideal train system mentioned earlier only exists in a few cities).