Editor's Note — Monthly Ticket is a CNN Travel series that spotlights some of the most fascinating topics in the travel world. In June, we're taking to the skies for a look at the latest developments in plane interiors, including the people working to change the way we fly.
(CNN) — There are some secret areas on widebody aircraft, where the pilots and cabin crew go to rest during long flights. Passengers can't access them under any circumstance and they're well hidden from view.
They're called Crew Rest Compartments and their location on the plane varies.
On newer aircraft, such as the Boeing 787 or the Airbus A350, they are located above the main cabin, in the upper fuselage. But on older aircraft, they can also be in the cargo hold or simply in the main cabin.
They come in pairs: one for the pilots, which usually sits above the cockpit and often includes two bunks and a recliner seat, and another for the cabin crew, usually containing six bunks or more and placed above the aft galley, the section at the back of the plane where food and drinks are prepared and stored.
Like a capsule hotel
Airlines have a say in the configuration of the crew rest areas when they purchase a plane, but the main parameters are set by regulators such as the Federal Aviation Administration. It mandates, for example, that the crew rest areas should be "in a location where intrusive noise, odors and vibration have minimum effect on sleep," and that they must be temperature-controlled and allow the crew to adjust lighting.
The bunks ("or other surface that allows for a flat sleeping position") have to be 78 by 30 inches (198 by 76 centimeters) in size -- tall people beware -- and have at least 35 cubic feet, or one cubic meter, of space around them. There also has to be a communal area for changing, entering and exiting that provides at least 65 cubic feet of space.
The crew rest area on a Boeing 777 passenger jet.
The end result is somewhat similar to a Japanese capsule hotel: a windowless, cramped, but cozy sleeping space, with power outlets and a light -- as well as all of the required safety equipment such as oxygen masks, seat belt lights and an intercom, among others.
"They can be quite comfortable," says Susannah Carr, a flight attendant with United Airlines who works on Boeing aircraft including the 787, 777 and 767.
"They have a padded mattress, an air vent to keep the air circulating and temperature controls so you can keep it cooler or warmer, and we're provided with linens, usually similar to the ones used in business class on our international flights. I like them -- but I'm also only about 5 foot 8 inches, so if you put a 6 foot 4 inch person in there, they might be a little tight," she says.
But are they better than a business or even first class seat?
"In some ways yes, in some ways no," says Carr. "The bunks can be wider than first class and for me personally, depending on the aircraft, I get more legroom. But it's a bunk, so you don't necessarily have the full head space of being in the cabin and obviously you don't have the privacy either. And if you're claustrophobic, you can definitely feel that there -- it's an airplane, so you only have so much space to put things. They certainly make use of every inch up there."
The rest area for the pilots is close to the cockpit.
The crew rest areas are designed to not attract too much attention from passengers, regardless of where they are located: "A passenger walking by would probably think it's a closet," says Carr.
"I won't go too far into how we access it -- it's secure, I will say that. Occasionally we have people that think it's a bathroom door and they try to open it, but we just show them the way to the actual restroom instead."
Behind the door there is usually a small landing and a ladder leading upstairs, at least on the latest aircraft.
"The bunks are either open on the side or one end, so you can crawl in -- I sometimes jokingly refer to them as 'the catacombs,'" says Carr.
On slightly older aircraft, such as the Airbus A330, the crew rest compartment can also be in the cargo hold, so a staircase would lead down instead. But on even older planes such as the Boeing 767, the rest areas are located in the main cabin, and are just recliner seats with curtains around them.
"They are very heavy curtains, they block out light and a good amount of sound, but not if you've got an energetic crowd on the plane or an upset child. We've had passengers open the curtains, looking for something or thinking they'd be going into the galley, so it's not necessarily the best rest."
Unsurprisingly, most flight attendants prefer the overhead bunks to the curtained seats, but the upgrade is beneficial to airlines too, who don't have to give up precious cabin space that can be used for passenger seats instead.
A split image of a Finnair A350 cabin crew rest area. On the right is the entrance, which is accessed from the forward galley.
Aleksi Kousmanen / Finnair
Cabin crew members on long haul flights usually spend at least 10% of the planned flight time in the rest areas.
"On average, I would say that means about 1.5 hours per long-haul flight," says Karoliina Åman, a flight attendant with Finnair who works on Airbus A330 and A350 aircraft. This, however, can vary depending on the airline and flight time -- rest time can extend up to a few hours.
"Since we don't have any private area in the aircraft for our lunch or coffee breaks, this rest period is extremely important and helpful for us," she says.
"This is the moment during the flight when we don't answer passengers' calls or do any other task but rest, and let our feet and mind have their break too. The purpose of this rest is to maintain an alert and ready mindset during the whole flight so that if anything unexpected happens, we are ready to take action."
Not everyone sleeps once in the bunk, however.
"Usually on an outbound flight from Helsinki I use my rest to listen to some audiobook or read a book since I am coming from home and am well rested. But on an inbound flight from the destination to Helsinki, there might be sleepless nights behind you -- for example I have trouble sleeping in Asia -- and then during the rest, you usually fall asleep. Waking up from that sleep can be a really harsh experience sometimes if your brain has switched to night sleep mode," says Åman.
To reach the rest area on this A330 SAS plane, cabin crew head down a small flight of stairs.
Philippe Masclet/master films/Airbus
"Jet lag can be a tricky beast," says Carr, "Sometimes I can unwind and I can sleep, other times my body's just not ready for a nap. But because we're on a break, we're allowed to use our phones, so we could watch a movie on it, or read a book."
The rest areas are closed during taxi, takeoff and landing, and they are used based on shifts overseen by the cabin manager -- or chief purser, in aviation lingo -- the cabin crew member who's in charge of all the others and supervises operations on board.
This person usually gets to use a special bunk that is near the entrance of the rest areas and has access to an intercom, to communicate with the pilots and the rest of the crew.
"Everything in our industry is seniority based, from the schedule you fly to the routes you can hold, to your days off," explains Carr. "The longer you've been there, the better the perks and one of those perks is picking your crew break time -- we go on seniority order, so the person who's the most senior on the flight gets to choose whether they prefer the first break or the second break, and then you go through the list until everyone has breaks."
The rest area for the pilots, which is separate from the one dedicated to the cabin crew, is close to the cockpit. Depending on the duration of the flight, there can be up to four pilots on board, but two will always be in the cockpit; therefore, the pilots' rest area only has two bunks (or even just one on older aircraft) but it includes a seat sometimes equipped with in-flight entertainment, which the cabin crew do not get. Other than that, the compartments are pretty similar.
"I usually sleep pretty well in there," says Aleksi Kuosmanen, deputy fleet chief pilot at Finnair.
Kuosmanen flies on A330 and A350 aircraft, and says he prefers the latter's rest area, which is located above the forward galley rather than in the main cabin. "It has really good curtains, you can adjust the temperature really well, there's great ventilation, and it's more soundproof. You don't hear anything of what's happening in the galleys, it's really quiet and comfortable."
On this Boeing 787 Dreamliner, the rest room for crew members is located at the back of the plane.
Roslan Rahman/AFP/Getty Images
The next time you're on a long-haul flight, you might want to keep your eyes peeled for an inconspicuous door at the front or the back of the plane -- if you see a pilot or flight attendant disappear into it, you might have spotted a rest area.
But keep in mind that crew members won't necessarily be happy to show you around, as passenger access to the rest areas is prohibited: "It's a little bit like Disney -- we keep the magic behind closed doors," says Carr.
"You don't necessarily want to know that your flight attendants are getting a little bit of shuteye, but at the same time you'll be happy when we pop up after our little cat nap all fresh as a daisy."
Top image: A rest room for pilots, located behind the cockpit of the Boeing 787 Dreamliner. Roslan Rahman/AFP/Getty Images