When I first saw this photo, I thought that someone had passed away during a flight and they had put the body inside a plastic bag. But this was not the case here, however.
Apparently, some orthodox Jews are forbidden to be in touch with dead people or even fly over a cemetery. The solution for this problem is to bag yourself inside a plastic bag during a flight.
As a non-overly religious person, it is very difficult to understand, why on earth someone would do something like this that has nothing to do with reality.