A smile at your neighbour-to-be, a quick check and an awkward squeeze as you sidle into your seat: 18A. Window seat, a coveted treasure! A clatter. Whoops! As you fumble for your dropped phone, your feet–which jut out ungracefully onto the aisle, end up as a speed bump for the wheels of someone’s carry-on. Yeowch!

It isn’t without more jostling that everyone finally settles into their seats, and with a scan at the window, the tarmac outside is looking busy. Hmm. It makes sense–this flight is just one of the 36.8 million trips around the world flown over the past year (International Air Transport Association, 2024).

Commercial aviation has clocked many miles since its first official iteration in 1914: a 27-km long “airboat” route established around Tampa Bay, Florida (National Air and Space Museum, 2022). Proving successful, it catalysed an industry and led to the establishment of carriers like Qantas, and the Netherlands’ KLM. 

Mechanics of Ascent (and Staying Afloat) 

As said Qantas plane pulls up in the window view, its tail dipped red with the roo taxies ahead of you on the tarmac. Your plane is now at the front of the runway queue and the engines begin to roar. You’re thrusted backwards as gravity moulds you to your seat. For a split second, as you look out the window, you can’t help but wonder–how on earth did you even get up here? How is this heavy, huge plane not falling out of the sky? 

The ability for a plane to stay afloat lies in its wings, which allow the plane to fly. The wings enable this through generating lift (NASA, 2022). Lift is described as one of the forces acting on an object like a plane, countering weight under gravity which is the force acting in the opposite direction, according to Newton’s Third Law (figure 1a). A plane's wings are constructed in a curved ‘airfoil’ shape with optimal aerodynamic properties: as pressure decreases above the wing with deflected oncoming air pushed up, the velocity increases, as per Bernoulli’s principle. This increases the difference in pressure above and below the wing, which remains high, generating a lift force that pushes the plane upwards (NASA, 2022) (figure 1b). 

Figure 1a. 

Forces that act on a plane.

Note. From Four Forces on an Airplane by Glenn Research Centre. NASA, 2022. https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/four-forces-on-an-airplane/. Copyright 2022 NASA.

Figure 1b.

An airfoil, with geometric properties suitable for generating lift.

Note. From Four Forces of Flight by Let’s Talk Science. Let’s Talk Science, 2024. https://letstalkscience.ca/educational-resources/backgrounders/four-forces-flight. Copyright 2021 Let’s Talk Science. 

Looking laterally, the thrust of a plane’s engines counters the horizontal drag force that airfoils minimise, all whilst maximising lift. Advancements in plane design over the mid-20th century focused on optimising this ‘Lift to Drag ratio’ for greater efficiency, a priority stemming from the austere, military landscape of World War II (National Air and Space Museum, 2022). Influenced by warplane manufacturing trends, the commercial sphere saw a transition from wooden to durable aluminium frames. In conjunction with this, double-wing biplanes were superseded by single-wing monoplanes (figure 2a, b), which had a safer configuration that reduced airflow interference whilst maximising speed and stability (Chatfield, 1928). 

Figure 2a.

A biplane, the De Havilland DH-82A Tiger Moth.

Note. From DH-82A Tiger Moth [photograph] by Temora Aviation Museum. Temora Aviation Museum, 2017. https://aviationmuseum.com.au/dh-82a-tiger-moth/.  Copyright 2024 Temora Aviation Museum. 

Figure 2b.

A monoplane, an Airbus A310.

Note. From Airbus A310-221, Swissair AN0521293 [photograph] by Aragão, P, 1995. Wikimedia Commons. https://commons.wikimedia.org/wiki/File:Airbus_A310-221,_Swissair_AN0521293.jpg CC BY-SA 3.0. 

Taking a Breather 

Without really noticing it, you’re somewhat upright again. Employing head shakes and gulps to make your own ears pop, you can also hear the babies bawling in discomfort a few aisles back. Blocked ears are our body’s response to atmospheric pressure changes that occur faster than our ears can adjust to (Bhattacharya et al., 2019). 

Atmospheric pressure describes the weight of air in the atmosphere above a given region of the Earth’s surface (NOAA, 2023), which decreases with altitude. Our bodies are suited to pressure conditions at sea level, allowing sufficient intake of oxygen through saturated haemoglobin within the bloodstream. Subsequently, the average human body can maintain this intake until 10000 ft (around 3000 m) in the air, with altitudes exceeding this likely to result in hypoxia and impairment (Bagshaw & Illig, 2018). 

Such limits have had implications for commercial flying. Trips in the early era were capped at low altitudes and proved highly uncomfortable: passengers were exposed to chilly winds, roaring engines, and thinner air, and pilots were forced to navigate around geographical obstacles like mountain ranges and low-lying weather irregularities. However, this changed in 1938 when Boeing unveiled the 307 Stratoliner, which featured pressurised cabins. Since then, air travel above breathing limits became possible, morphing into the high-altitude trips taken today (National Air and Space Museum, 2022).

Via a process still relevant to us today, excess clean air left untouched by jet engines in combustion is diverted away, cooled, and pumped into the cabin (Filburn, 2019). Carried out in incremental adjustments during ascent and descent, the pressure controller regulates air inflow based on the cockpit’s readings of cruising altitude. Mass computerisation in the late 20th century enabled precise real-time readings, allowing safety features like sensitive pressure release valves, sensor-triggered oxygen mask deployment, or manual depressurisation. 

However, the sky does indeed dictate the limits, as pressure conditions are simulated at slightly higher altitudes than sea level to avoid fuselage strain (Filburn, 2019). This minor pressure discrepancy plays a part in why we feel weary and tired whilst flying–our cells are working at an oxygen deficit for the duration of the flight. 

Your yawn just about now proves this point. Time for your first snooze of many…

Food, Glorious Food 

A groggy couple of hours later and it’s either lunch time or dinner, your head isn’t too sure. You wait with bated breath, anticipating the arrival of the flight attendant wheeling the bulky cart through the narrow aisle...

Only to be met with a chicken sausage that vaguely tastes like chicken, with vaguely-mashed potato and a vaguely-limp salad on the side. Oh, and don’t forget the searing sweetness of the jelly cup!

You’re far from alone in your lukewarm reception of your lunch-dinner. Aeroplane food remains notorious amongst travellers for its supposedly flat taste. Whilst airlines like Thai Airways and Air France have employed Michelin-star chefs to translate an assortment of gourmet cultural dishes to tray table fare (De Syon, 2008; Thai Airways, 2018), the common culprit responsible for the less-than-appetising experience remains – being on a plane. 

As Spence (2017) details, multiple factors play into how you rate your inflight dinner, many relating to the effects of air travel on our bodies. The ‘above sea level’ air pressure within the plane coincides with higher thresholds for detecting bitterness at 5000-10000 ft (around 1500-3000m), heightening our sensitivity to the tart undertones of everyday foods. Dry pressurised air that cycles through the cabin is about as humid as desert environments, which hampers our smell perception and thus taste. Less intuitively, the loud ambient noise of the plane’s engines also appears to hinder olfactory perception, though the reason as to why remains unclear. 

Nevertheless, alleviating the grumbling passenger and stomach is an area of interest with a few successful forays. One angle of approach involves food enhancement. Incorporating sensory and textural elements into meals such as chillies and the occasional crunch or crackle can compensate for impaired perception. Interestingly, umami has been observed as the least affected taste sense mid-air (Spence, 2017), inspiring British Airways’ intense and aromatic umami-rich menus – though with the unwitting drawback of threatening to stink up the plane on multiple occasions (Moskvitch, 2015). Meanwhile, Singapore Changi Airport houses a simulation chamber for food preparation in a low-pressure environment, taking it up a notch in both quality and cost (Moskvitch, 2015). 

Alternatively, passengers can be psychologically tricked into perceiving food to be more appetising than it is in reality. Some examples of this include the use of noise-cancelling headphones, cabin lighting designed for enhancing the appearance of food, or appealing language for describing meals. Both off-ground and in air, it was found that humans were inclined to respond more positively to dishes described in an appetising and detailed manner (Spence, 2017), rather than the vague choices of “sausage or pasta”. 

Whilst these innovations have covered some ground, De Syon (2008) also notes that sociology can influence our perceptions of food on a plane. The enjoyment of meals is dependent upon core social rituals like dining communally or comforting meal-time habits–both of which are tricky to navigate and achieve on a packed plane with front-on seating. 

What Goes Up Must Come Down

Not long now! Accompanied by the movies you’ve played for the first time in your life and oodles of complimentary tea, there’s about half an hour left until landing. Jolt! The seatbelt sign is bold and bright as you can feel the plane gradually descending–it’s getting bumpy! 

As your plane rocks about and the airport comes into view as a speck in the distance, your descent is at the mercy of the crosswinds… and turbulence? Not only do these vortices of air cause havoc mid-flight, near cloud bands and thunderstorms (National Weather Service, 2019), they also pose a challenge during landing in the form of local, “clear-air” convection currents invisible on radar. 

These currents often occur in summer months and in the early afternoon when incoming solar energy is at its highest. In particular, they emerge when the surface of the earth is unevenly heated, including across regions such as the oceans, grassland, or in this case, the pavement near the airport. Consequently, this creates pockets of warm and cool air that rapidly rise and fall, creating downdrafts, thereby trapping planes (figure 3). Luckily, pilots are specifically trained to recognise these surface winds, and can adjust their landing glidepath to suit local conditions forewarned in Terminal Aerodrome Forecasts for a steady, controlled descent (BOM, 2014). 

Figure 3.

Varying glidepath due to local convection currents - note the different types of surfaces.

Note. From Turbulence by National Weather Service. National Weather Service, 2019. https://www.weather.gov/source/zhu/ZHU_Training_Page/turbulence_stuff/turbulence/turbulence.htm. Copyright 2019 National Weather Service.

Even with its bumpier experiences that draw endless complaints, it is undeniable that commercial aviation has grown tremendously over the century to deliver the safe, efficient and comfortable flights we are accustomed to today. Building upon a history of ingenuity and scientific discovery, it's almost certain that the industry will soar to even greater heights in our increasingly globalised world.

Enough talk–you’re finally here! It’s a relief when you clamber from your seat, giving those arms and legs a much needed stretch. Now, time to trod along on solid ground…

…and onto the connecting flight.

Cheap stopover tickets. 

Darn it.

References

Aragão, P. (1995). Airbus A310-221, Swissair AN0521293. Wikimedia Commons. 

https://upload.wikimedia.org/wikipedia/commons/9/9b/Airbus_A310-221%2C_Swissair_JP5963897.jpg  

Bagshaw, M., & Illig, P. (2019). The aircraft cabin environment. Travel Medicine, 429–436. https://doi.org/10.1016/b978-0-323-54696-6.00047-1 

Bhattacharya, S., Singh, A., & Marzo, R. R. (2019). “Airplane ear”—A neglected yet preventable problem. AIMS Public Health, 6(3), 320–325. https://doi.org/10.3934/publichealth.2019.3.320 

BOM. (2014). Hazardous Weather Phenomena - Turbulence. Bureau of Meteorology. http://www.bom.gov.au/aviation/data/education/turbulence.pdf 

Chatfield, C. H. (1928). Monoplane or Biplane. SAE Transactions, 23, 217–264.

http://www.jstor.org/stable/44437123 

De Syon, G. (2008). Is it really better to travel than to arrive? Airline food as a reflection of consumer anxiety. In Food for Thought: Essays on Eating and Culture (pp. 199–207). McFarland.

Filburn, T. (2019). Cabin pressurization and air-conditioning. Commercial Aviation in the Jet Era and the Systems That Make It Possible, 45–57. https://doi.org/10.1007/978-3-030-20111-1_4 

International Air Transport Association. (2024). Global Outlook for Air Transport. https://www.iata.org/en/iata-repository/publications/economic-reports/global-outlook-for-air-transport-june-2024-report/ 

Let’s Talk Science. (2024). Four Forces of Flight. Let’s Talk Science.

https://letstalkscience.ca/educational-resources/backgrounders/four-forces-flight 

Moskvitch, K. (2015, January 12). Why does food taste different on planes? British Broadcasting Corporation. https://www.bbc.com/future/article/20150112-why-in-flight-food-tastes-weird 

NASA. (2022). Four forces on an Airplane. Glenn Research Center | NASA. https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/four-forces-on-an-airplane/ 

National Air and Space Museum. (2022). The Evolution of the Commercial Flying Experience. National Air and Space Museum; Smithsonian. https://airandspace.si.edu/explore/stories/evolution-commercial-flying-experience 

National Weather Service. (2019). Turbulence. National Weather Service. https://www.weather.gov/source/zhu/ZHU_Training_Page/turbulence_stuff/turbulence/turbulence.htm 

NOAA. (2023). Air pressure. National Oceanic and Atmospheric Administration. https://www.noaa.gov/jetstream/atmosphere/air-pressure 

Spence, C. (2017). Tasting in the air: A review. International Journal of Gastronomy and Food Science, 9, 10–15. https://doi.org/10.1016/j.ijgfs.2017.05.001 

Temora Aviation Museum. (2017). DH-82A Tiger Moth. Temora Aviation Museum.

https://aviationmuseum.com.au/dh-82a-tiger-moth/ 

Thai Airways. (2018). THAI launches Michelin Star street food prepared by Jay Fai for Royal Silk Class and Royal First Class passengers. Thai Airways. https://www.thaiairways.com/en_ID/news/news_announcement/news_detail/News33.page