Not to be crass, but we're inclined to think these masks not only aid in the act of sex, but enhance it. Do you see how these two are posing? Is there any evidence to suggest that she didn't spend the entire flight riding this wily-eyed clydesdale like a stallion? Why do you think she's so tired?
Their guttural moans of pleasure just echoing through the back of the plane as the dude's actual wife slowly dies from respiratory failure in their suburban living room from scarlet fever.