Go Ahead and Relax!
Few things are more uncomfortable than gruelingly long flights on a plane. As hectic as they can be, it doesn’t give anyone a free pass to encroach on someone else’s personal space. Hopefully those seats aren’t taken.
Not only is it distasteful to be barefoot on a flight, judging by this person’s feet, we can also tell that they are most likely full-grown adults. This also means that, as an adult, they should know what basic etiquette is. Clearly, this person doesn’t.