What's up with airplane food? Why does it taste so weird? How has it become a lazy punchline at best, and a source of dismay for disgruntled passengers, at worst?

Whether frequent flyers or not, most passengers have a love-hate relationship with in-flight food. Some people will order everything on the menu and go back for seconds (yes, you can do that), while others won’t touch it with a barge pole. But love it or loathe it, behind its flimsy plastic wrap, airplane food is surprisingly complex.

The science of taste at 40,000 ft is a multi-billion dollar industry and most airlines work hard to make sure their passengers enjoy their experience as much as possible, including the food they eat. Believe it or not, meticulous planning goes into every aspect of your on-board meal, from seasoning, texture to ingredients, and airlines go to insane lengths to taste-test their menus.

Many of us actually know very little about the food we eat in the sky and how it’s made, but dig deeper and you’ll discover lots of weird and awesome facts, more interesting than the bland cuisine itself. Here’s our rundown of 20 crazy facts about in-flight grub - you’ll never look at plane food the same way again.

20 20. Don’t Blame The Chef: Science Has Proven That Food Tastes Weird In The Sky

It turns out that the human body has some interesting reactions to being stuck in a pressurised tube thousands of feet above the ground. Both food and beverages taste odd at 30,000 ft and it’s due to a combination of low pressure, low humidity levels and loud engines - all factors that dampen one’s ability to taste.

In fact, your ability to taste sweet flavours drops 15 to even 20 percent and saltiness drops 20 to 30 percent, and some airlines try to circumvent this issue by drastically increasing the levels of salt and sugar in their meals. The fact remains, however, that food won’t taste the same, and it's not the cook's fault.

19 19. Airline Food Is Nearly 100 Years Old (And Probably Tastes Like It...)

We know some airline food tastes like it might be 100 years' old, but what we actually mean is that food has been served on-board for nearly a century. On October 11 1919, Handley-Page served the first in-flight meals on their London to Paris route. For three shillings, passengers could purchase a pre-packaged lunch of a sandwich and fruit.

Handley Page Transport Ltd was an airline company founded in 1919 by Frederick Handley Page in the new era of civil flying after the WWI. A single fare cost around £4 10 shillings, the equivalent of more than £500 in today’s money.

18 18. Food Used To Be Cooked On Planes (By Actual Chefs)

Before the strict regulations regarding air safety were implemented, flying was a vastly different experience. Not only could you smoke during the flight, but a lot of food served was cooked on the plane itself. In 1936, United Airlines installed the first on-board kitchens to provide air passengers with hot meals, and other airlines soon followed suit. Launched in 1969, Concorde became renowned for its high-quality cuisine, much of which was prepared on board. Menus included Champagne, caviar, black truffle, foie gras, and lobster with saffron.

17 17. Nowadays, All Food Is Made On The Ground

All airplane food is cooked and prepared on the ground to comply with safety laws. You can’t cook onboard, because any open flames are a serious safety hazard while the plane is in midair, obviously.

Since airplanes don’t have a proper kitchen with proper appliances, your food is just reheated by cabin crew using a convection oven that just blows hot, dry air over the food to heat them up and stay hot.

Big airline food manufacturers such as LSG Sky Chefs produce 15,000 bread rolls every hour, 24hrs a day, 365 days a year, and 30,000 sandwiches a day.

16 16. Sonic Seasoning: Wearing Headphones Will Make Your Food Taste Better

In addition to taste and smell, your hearing can also affect how you experience food. According to recent studies from Cornell University, a loud auditory environment, like the pressurised cabin of an airplane, can change our food/taste perception.

Researchers had 48 men and women consume liquid solutions of the five basic flavours - sweet, salty, sour, bitter, and umami - in a room with regular ambient noise, and again in a room with simulated airplane noise. The results? Louder noises make us perceive foods as less sweet with a more pronounced umami flavour.

Therefore, listening to music on your headphones, or wearing noise-cancelling headphones, can make your food taste better, and airlines are getting increasingly creative with the links between taste, sound, noise, and music. In 2014, for instance, British Airways unveiled a feature on their flights entitled “Sound Bites,” where people could tune into a specially-curated playlist meant to enhance the flavours in their food, and enjoy, say, Verdi operas while digging into pasta.

In normal, everyday life on the ground, people seemingly don’t order tomato juice that often. But 30,000 ft in the air, however, and suddenly it’s in demand, being ordered by people who would never normally drink it. Have you ever considered why this is?

According to a clinical study by Lufthansa Airlines, fluctuating air pressure of aircraft cabins makes passengers crave acidity and saltiness, which tomato juice satisfies. While on the ground, it tastes earthy, in the air, it’s sweet and salty. Tomato juice just tastes better in the air.

14 14. A Lot Of Thought Goes Into Selecting The Best Wines To Enjoy At 36,000 Feet

If you’ve read this far, you’ll know that our palates change at altitude due to a number of factors, but these changes affect what’s on the wine menu, too. Wines that are more acidic and high in tannins aren’t as enjoyable in-flight, so most airlines tend to carry fragrant and fruity wines instead.

With such enormous customer demands, airline wine is a multimillion dollar business that can prove a boon to any national wine industry. Qantas alone claims to invest $25 million in the Australian wine industry every year.

13 13. Airlines Throw Away Food If A Flight Is Delayed

All uneaten food gets thrown away immediately after every flight, and when you consider that Emirates' catering alone facility prepares 180,000 meals to service its more than 400 daily flights around the globe, and there are similar operations across the world, you’ll realise that the scale of in-flight catering, and waste, is astonishing.

But what’s worse is that the food on a plane also gets thrown out if the flight is delayed for more than six to eight hours. Yes, all of it.

According to the International Air Transport Association, airlines produced 5.2 million tons of waste in 2017, and will produce over 10 million tons annually by 2030. Thankfully, airlines are waking up to the problem and are increasingly finding ways to divert cabin waste from landfills.

12 12. It’s Okay To Ask For More Food

As you read above, all uneaten meals get chucked, so if one airline meal isn’t enough for you, you really can ask for more (providing you ask cabin crew nicely).

It’s not just meals either. Many of us think that once we are provided with a snack, that's it, no more snacks. But again, if you want another bag of pretzel pieces, you can politely ask - just don't tell the sleeping passenger beside you.

11 11. Spoiler Alert: Airplane Food Isn't Fresh

Don’t be fooled by those pesky “freshly prepared” stickers on your in-flight sandwich. Airplane food can be made anywhere from 10 hours to 72 hours beforehand. In fact, in Europe, it’s totally legal to have the food chilled for up to five days before serving.

Hot dishes are made in large industrial pans and decanted into plastic containers with foil lids before being blast-chilled to around 5C in 90 minutes. Out of the facts about airplane food, this one is probably the easiest to believe.

10 10. Airlines Can Save Thousands Of Dollars By Altering Just A Single Ingredient

Airlines meticulously plan their in-flight menus at least six months in advance, and sometimes up to a full year ahead of time, and one of the main reasons for this is financial.

AA famously saved $40,000 a year in 1987 by getting rid of just olives from their salads. Delta saved $250,000 a year by shaving just one ounce from their steaks, and AA also removed a single strawberry from their in-flight fruit salads and saved a whopping $210,000 a year.

9 9. In-Flight Catering Is A Billion Dollar Industry

The global in-flight catering services market reached USD 15.54 billion in 2017 and the market size is expected to grow to $18 billion by 2021. Asia-Pacific accounted for the largest market, of around one-third of the global market share, and LSG Sky Chefs - the brand name of LSG Lufthansa Service Holding AG - is the world's largest provider of airline catering, partnering with 300 airlines worldwide across 214 airports, producing a whopping 591 million meals a year.

8 8. The Saucier The Better

The motto is ‘the saucier the better’ when it comes to airline food. Not only does the air at a high altitude dry out your sinuses, but scientists also say the lack of humidity causes food to dry out.

Sauce-based dishes such as stews and curries fare better as in-flight meals because they are moist by nature, so are likely to be more tender and flavoursome. That’s why most airlines tend to have saucy dishes, and why you should try to order them when you can.

7 7. The Meats Aren't Cooked Through (On The Ground, That Is)

Whether it’s chicken, lamb or beef, the meats that you pick from the plane's menu aren't fully cooked when they leave the industrial kitchen on the ground. Beef is actually cooked only 30 percent and chicken only 60 percent, before being loaded on to the plane. But there’s nothing to be worried about, because the meat is then cooked all the way through in the on-board steam or dry-air convection oven.

6 6. There Are No Microwaves On Board

While airplane food often looks and tastes like it’s been nuked by a microwave, you won’t actually find a microwave on any commercial airplane. That’s because both microwaves and conventional ovens are prohibited for safety reasons.

Instead, dry-air convection ovens are the most common tool used to reheat your food, but they aren't perfect and tend to dry out meals. Culinary scientists are working on ways to ensure food stays tasty after being reheated. New types of ovens are used on certain flights, and many airlines have begun steaming food to keep moisture in dishes.

5 5. Pilots Eat Different Meals To Passengers

“The life of everyone on board depends upon just one thing: finding someone back there who can not only fly this plane, but who didn't have fish for dinner.” If the movie Airplane! taught us anything, it’s that the flight crew should never eat the same meal as passengers.

Thankfully, due to very stringent safety regulations, it’s super rare for airplane meals to give you food poisoning. However, it’s still important to give pilots and co-pilots different meals to prevent them getting sick, just in case. Because if those in charge of the plane suddenly get an upset stomach, it won’t be a pretty flying experience for anybody.

4 4. Umami - The Savoury Fifth Taste Sensation - Is Unaffected By Altitude

Umami, the fifth taste besides salty, sweet, sour, and bitter, is the only taste that is unaffected at such a high altitude. If anything, scientists have claimed it’s enhanced.

Umami, beloved by Japanese chefs, is that satisfying, savoury taste you get from foods such as tomatoes, sardines, shellfish, and soy sauce. That’s probably why you see so many in-flight meals packed with umami-rich ingredients such as spinach, mushroom and fish, not to mention all the tomato juice served on board.

3 3. Culinary Science Goes Into Every Mouthful

The process for creating on-board meals, from fully-designing to implementing menus, involves lots of trial and error and can take more than a year. United’s Polaris menu, which launched in 2016, included 28 menu workshops in 16 cities on five continents to produce 48 new salads, 96 appetisers and 240 entrees.

Science and culinary arts combine when creating plane food. Virgin, for example, always choose proteins that can survive if the seatbelt sign goes on and the food is stuck in the oven. Salmon, kingfish and barramundi are all high in oil content which is good, and meat that has a little bit of fat also keep their texture well. Airlines would never use a loin of venison because it’s got no fat and if it’s overcooked, it’s going to be like leather.

2 2. Even Celebrity Chefs Have Tried To Make Plane Food Taste Good

Many airlines have turned to celebrity chefs to bring not only taste, but also a bit of glamour, back to flying. Australian airline Qantas pioneered the concept of partnering with celebrity chefs in 1997 when it brought aboard Neil Perry, who put Aussie fine dining on the map at his flagship restaurant, Rockpool.

Air France decided to capitalise on its national culinary heritage by asking Michelin-starred chefs from around the country to create the menus for its first and business class passengers.

Not to be left out, British Airways challenged gastronomic guru Heston Blumenthal to create the ultimate in-flight meal. The result was “Height Cuisine,” a menu designed to maximise the taste of its dishes at altitude by using recipes that are naturally high in umami.

1 1. Not Eating During A Flight Can Actually Be Bad For You

Those who refuse to eat airplane food or simply hate eating while flying aren’t making the healthy choice. Not eating on the plane is pretty bad for your health because it can cause your blood sugar levels to drop, which results in you feeling fatigued, weak, and shaky.

Not eating can also cause migraines and drastically changes your mood, too. And as for jet lag, not eating can worsen the effects. So, next time you fly, make sure you either brave the on-board food, or take your own.

References: bbc.co.uk, flightcentre.com