Between the routine disruption, free-flowing drinks, overuse of hand sanitizer and dry airplane cabins, staying hydrated while flying is no small feat. But it’s one of the most vital steps to ensure you arrive at your destination feeling fresh and ready to go.

“When at altitude, commercial airliners bring in outside air as part of the normal circulation process,” explains Bob Bacheler, managing director and in-flight nurse at Flying Angels. “One advantage of this is air is exchanged more often than [almost] any other building, making the air safer to breathe from a viral transmission perspective. The downside of this is the lack of humidification, usually around 15% to 20%, which is half of what people find comfortable.”