Where in that spectrum do you figure people without money fit?
If you're relocating because that's where your new job is, you're probably flying.
If you're stranded across the country from a family member that needs help, you're flying.
If your car won't likely handle the trip, you're flying.
If you've been staying with family and are now required to return to work immediately, you're flying.
There are plenty of reasons people would travel and fly unwillingly, and it's not likely that someone with limited financial resources can arrange alternate accommodations. Having more money means having more options. Sometimes "don't go anywhere" is just too expensive.
It's not just about flying... People with higher incomes are more likely to be able to work from home, take vacation time, weather furloughs or layoffs, and live in communities where they can be more isolated. They can afford to have supplies delivered to them, have indoor entertainment, and have direct access to support services. Their overall risk profile is much lower than someone without those options.
Of course, once we start talking about upper-class options, the risk drops even further. Vacation homes, private aircraft, work delegation, black-market suppliers, resource stockpiles, VIP healthcare... For only a few million dollars, the ultra-rich can simply leave society and wait for things to settle down, confident in having essentially no exposure.