If you have ever been caught short with a toilet nowhere to be seen, spare a thought for fast jet pilots who must wee in a cramped cockpit travelling at more than 1,000 miles per hour.
With air refuelling allowing for longer flights that can last for several hours at a time, pilots cannot risk just 'holding it in' - that is not an option.
They have a need for speed but also, at times, a need to wee so how do they manage the task, thousands of feet up in the sky?
The problem of relieving a pilot's bladder while flying a fast jet has been around for decades.
Pilots were choosing tactical dehydration by not drinking water during flights to prevent having to go to the toilet at all.
Jeff Devlin from Skyborne Airline Academy is a former US Marine Corps F-18 fighter pilot. He explained why planning bathroom breaks is essential to operational effectiveness, saying: “Mission times vary greatly. An air-to-air dogfighting training mission can be less than an hour, while a mission that involves aerial refuelling could last 6 plus hours.
"Every good pilot takes a bathroom break right before walking out the door.
"For longer missions, it’s common not to drink too much inflight but that can lead of course to dehydration and possible diminished operational effectiveness.”
Dehydration can cause headaches, reduced endurance and G-force tolerance while in the aircraft - all essential to avoid to ensure accurate flying.
Improving in-flight comfort and safety increases performance which in turn improves capability.
Major Nikki Yogi, an F-35A Lightning II US Air Force pilot who participated in tests to find a new way to help pilots relieve themselves while in the air, is adamant that removing barriers to readiness must be a priority.
In a USAF press release, she explained why, saying: "A pilot should be focused on taking the fight to the enemy, not on whether their bladder relief device is going to work or be comfortable to use."
The tests Maj Yogi took part in resulted in the creation of the Omni Gen. 3 Skydrate which is an upgrade to the existing Advance Mission Extender Device (AMXD) - a bladder relief device that can be worn throughout the flight and is designed to detect urine and pump it away allowing the flight to continue without interruption.
It's not only the US Air Force that is looking to improve in-flight bladder relief.
A senior Royal Air Force source said that the RAF has been "heavily involved in research and development of a variety of devices and have been instrumental in offering feedback to improve systems with the RAF Centre for Aviation Medicine (RAF CAM) being a world leader in this area."
The source went on to say that the RAF is also assisting in the development of the Skydrate system, saying: "This was party developed using RAF feedback and the Department will be evaluating it for possible future use, however, no decision has been made on whether it will be brought into service."
"RAF CAM and Kings College London have recently completed a study on this issue.
"The RAF have and will continue to conduct inflight trials of a variety of appliances including the AMXD & 'Skydrate' urination devices."
Skydrate is available for men and women but after feedback from female pilots, more work was done to improve the design and effectiveness of the pad. US aircrews are due to receive Skydrate by Spring 2022.
How do fast jet pilots pee?
American pilot Lieutenant Colonel Don Snelgrove crashed into a Turkish hillside while trying to relieve himself in his cramped F-16 cockpit in September 1992.
The pilot was able to eject safely and no one was hurt on the ground, but the USAF did lose $18 million worth of aircraft and all because Lt Col Snelgrove needed to urinate.
It is crucial for pilots to be able to focus solely on the job at hand.
They cannot simply land their aircraft at a service station and pop in quickly to relieve themselves as they could if they were on a road trip.
The RAF use multiple systems such as the AMXD which is already in use by UK aircrew.
Former US Marine Corps F-18 fighter pilot Jeff Devlin explains that most pilots are able to delay a bathroom break until landing for missions between four to five hours, but any longer than that and bladder relief devices are used, saying: "We used what were called relief packs - the slang term was 'piddle pack'.
"This was essentially a thick plastic bag with a sponge inside of it, and an integrated seal.
"These packs are also commonly used for ocean crossings that take 10 plus hours."
One method described by Colonel Samantha Weeks, Commander, 14th Flying Training Wing in a US Department of Defense training video for the US Air Force bomber/fighter community (you can see the video at the top of the article), uses a piddle pack – it's not very glamorous but it gets the job done, albeit rather uncomfortably in a tight cockpit.
Below is a step-by-step guide to urinating while flying an F-16. Other devices are also available for fast jet aircrew including pouches that you use external to your flight suit via a tube, adult nappies and modern systems such as the AMXD.
Set the autopilot
Making this the first action will give the pilot more freedom to move inside the jet and hopefully still keep an eye on their altitude, air speed and so on. Also, they must ensure they urinate during a non-tactical phase of the flight and inform other pilots they are flying with. Priority number one must be safety.
Get into position
Next, the pilot must use their heels to help push themselves off the seat a small distance so they can place what is known as a piddle pack onto or near their body. For women, it is essential to press the entrance of the piddle pack hard against themselves to reduce any spillages.
The pilot must check that the piddle pack is fully open to ensure the successful collection of urine. It is also essential that the pilot is not sat on the piddle pack, so women are advised to lift themselves up a few inches to allow for this.
Using one hand so they can still have some control over the aircraft, the pilot should then move their underwear out of the way, place the piddle pack securely into position and urinate.
Just like a nappy
Piddle packs contain absorbent material that soaks up liquid in the same way a nappy does. The urine becomes a gel-like substance and can be sealed in the piddle pack and hidden somewhere safe for the rest of the flight.
Practise makes perfect
With more than 15 years of experience behind her, Col Weeks recommends that pilots should practice the process a few times over a toilet before trying it in the air.
Oh, and before you ask how they poo while flying, they don't.
Cover image: An F-35B Lightning Jet (Picture: Crown Copyright).