Despite their fame and fortune, many celebrities still have to cross paths with mere mortals if they need to travel by plane. Flying private isn't always an option, or it's just too expensive, as Chrissy Teigen once addressed in a tweet. And so, celebrities get spotted on planes with the rest of us, probably in first class but sometimes even in coach (looking at you, Prince William and Jessica Alba).

Twice this year, A-listers on planes have made headlines - not just because they were on board in the first place, but because of their germ-fighting plane rituals.

First came supermodel Naomi Campbell, who posted her plane sanitizing routine on her YouTube channel. After boarding her Qatar Airlines plane bound for Doha, Campbell pulls out disposable gloves from her massive Louis Vuitton carry-on bag, then Dettol Anti-Bacterial Cleansing Surface Wipes.

"Clean everything you touch," Campbell says as she wipes down every nook and cranny of her premium seat. " . . . This is what I do on every plane I get on. I do not care what people think of me. It's my health and it makes me feel better."

Months later, it was Nicole Richie's gloves and antibacterial wipes routine that made news when supermodel Heidi Klum posted about her travel companion's extreme cleaning routine. The video isn't as lengthy as Campbell's, so we don't get a good look at just how thorough Richie gets beyond three Wet Ones.

Are these germ-conscious celebrities on to something? Should other travelers be following suit?

"It's certainly going a bit overboard," says Tania Elliott, attending physician at NYU Langone Health and a board-certified allergist and internist. "That said, is there necessarily harm in doing this? I don't think so."

Elliott thinks most people worry about germs on airplanes because of the recirculated air but that it doesn't need to be a concern. She says breathing in a plane's recirculated air won't increase your chances of picking up a virus any more than being in any other crowded space.

The Centers for Disease Control and Prevention is on the same page. Commercial jets built after the '80s are outfitted with efficient air filtering systems that should put anxious minds at ease.

"Recirculated cabin air is filtered through HEPA (high-efficiency particulate air) filters," a CDC post on healthy flying states. "These effectively remove most bacteria and viruses from the air, limiting their spread through the cabin. Practice good handwashing and cover your mouth when coughing or sneezing to further prevent the spread of disease."