First, the good news: Air in airplane cabins is heavily filtered and safer than most indoor environments, with cabin air completely replaced every three minutes while the plane is in flight, per National Geographic. At the same time, you can keep yourself even safer on board with some simple but strategic modifications. Read on for a smart hack you should know before you board your next flight from Thomas Russo, MD, a professor and chief of infectious diseases at the University at Buffalo. RELATED: Never Say These 2 Words to a Flight Attendant, Expert Warns. If you’re lucky enough to be on a flight that still has meals, you’ll be served at the same time as other passengers near you, as the flight attendants make their way down the aisles with the cart. The same goes even for light snack service. But hungry as you may be, don’t eat as soon as you’re served, Russo warns. RELATED: Never Wear These Shoes on a Plane, Flight Attendant and Pilot Warn. Instead, wait till those around you are done, and then take off your mask to eat. This way, you allow time for other passengers to finish their meals and replace their masks before you take your own mask off to eat, an action that briefly leaves you (and others around you) more vulnerable.ae0fcc31ae342fd3a1346ebb1f342fcb “When the food first comes, the reaction is everyone drops the masks and eats the meal or the snack that they give you,” Russo says. “What you should do instead is actually be patient. You wait until everyone’s done and puts their mask back up, which usually takes somewhere between 15 and 30 minutes, and then that’s when you should go ahead and eat your meal.” It’s also good practice to replace your mask over your nose and mouth even as you eat, between bites and sips, for maximum protection—and to abide by airlines’ policies. “The advice I use on the plane is to avoid dropping your mask if possible,” Russo says, “but if you have to drop your mask when you’re on the plane, pop your mask back up between bites.” RELATED: For more health advice delivered straight to your inbox, sign up for our daily newsletter. It’s not just mask mandates that airline passengers must be aware of this holiday season. Other inconveniences include the possibility of canceled flights (or significantly delayed flights) amid the staffing shortage brought about by the pandemic. Southwest Airlines recently canceled nearly 2,000 flights, stranding travelers and creating chaos in airport terminals and for customer service agents across the country. Be prepared for even more challenging holiday travel strain than usual. RELATED: Never Do This When Your Flight Is Canceled, Travel Expert Warns.