Flying can cause dehydration due to the limited oxygen at high altitude.

While airline passengers can bring bottled water on board in their carry-on bag, only a small size and quantity is allowed for security reasons.

For travelers who need to drink more water during a flight, they have the option to bring an empty bottle and refill it at the airport’s departure area after the security screening, or simply drink the water provided onboard.

X user @SolBrah has an alternative that he recently posted on the short messaging platform.

“Flying ProTip: You cannot travel with full water bottles but you can travel with a full unopened coconut. Arrive at your destination fully hydrated,” read his post on @SolBrah, the Daily Mail reported.

Coconut juice is said to be better than water for hydration as it contains minerals and electrolytes — potassium, sodium and manganese.

Some commenters welcomed the idea but others said opening a coconut may require “a knife or sharp object, if not smashing a hole in it with a hatchet.”

A coconut, however, can be brought onboard already opened with the hole sealed with tape or a straw.

Hydration during a flight is as important for pilots as flight passengers. For military pilots, they face an added problem: holding their pee.

Veteran fighter jet pilots of the United States Air Force and Navy told Aerospace Global News (AGN) that a lack of water lowers their G-force tolerance, which can cause them to pass out or blur their vision while flying.

Not urinating during long aerial missions, meanwhile, causes brain fog, fatigue, night vision issues, constant headaches, irritation and bladder damage.

The problem is being addressed with the introduction of a bladder relief device integrated into the gear that allows pilots to comfortably pee in the cockpit mid-flight without unstrapping or removing equipment, thereby eliminating the need for pee bags or risky cockpit maneuvers, according to AGN.

The hygienic device called Skydrate can also detect when a pilot needs to pee and safely channels the urine into a secure collection unit.