What's the MPG of a Plane?

It's no Prius, but it's... better.

Jan 28, 2021

Let’s start by stating that flying makes mother nature pretty upset. But at least you spend less time disappointing her. Objectively, planes burn more fuel in one flight than you can really comprehend. Let’s look at a flight from New York to LA: since you’re flying through the air, your route is basically a 2,500-mile straight line across the country. According to Google Maps, if you were to drive from coast to coast, best case you’re looking at about 2,800 miles. That obviously starts to put the eco war in the plane’s favor. On average, you need to go 300 fewer miles when flying between these two cities. We can’t, however, write the car off just yet. To give ourselves a fighting chance, let’s look at a Prius – the shining beacon of hybrids (or at least was). The Toyota Prius is a fabulous machine. It has two separate engines that work together to give you enough power to jusssst barely merge onto the highway, all while delivering the best possible fuel economy. Our car must use gas, or else it wouldn’t be much of a comparison, but we will do some quick math later to see how our plane stacks up against a Tesla as far as carbon emissions (it's closer than you’d think).

The 2021 Prius gets a reported 53 mpg highway – compared to the average fuel economy of the plane – 0.47 mpg. That seems like a clean sweep for our hybrid. The trip for the Prius would burn about 53 gallons of fuel compared to the plane’s fuel load of 5,325 gallons. Okay, great, problem solved, thanks for reading!

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Wait wait wait. It’s just you in the car. That’s not fair. Our zoomy tube can carry anywhere between 140 and 220 passengers depending on the model (based on most common flights between JFK and LAX). Therefore, per person, while flying you would achieve a fuel economy of roughly 65 mpg. The plane burns way more fuel over this journey—about 100 times more—but because the plane can carry much more than 100 times the passengers, the math works out in the plane’s favor. So, there you go! Your best bet is the plane. That is, unless you were to take the whole family. By the same logic as the plane, if you were to pile your family of four in the car with you, your per person fuel economy would be 250 mpg. That gives a much better result than the plane. The only problem here is you have to deal with your kids in a confined space for three days. Pick your poison.

So, at this point we’ve determined that, if you’re by yourself, the most environmentally prudent choice would be to fly. (Actually, it would be to walk) But how does that stack up in terms of cost? If we were to consider the price of plane tickets during COVID times, it would be a no brainer. JetBlue, Delta, and American all currently offer one-way flights from JFK to LAX for $99. However, the average cost of such a journey would normally run you about $350. A lot of things go into pricing this ticket; fuel, capital costs from buying the aircraft, crew, maintenance, landing and takeoff fees, etc. Surprisingly, though, the driving factor is what airlines can get away with charging you based on their competitor’s rates. Airlines are very rarely profitable, because they just keep driving their prices lower to try to gain a share of that route. How the airline pricing model works is for another, much sadder newsletter. If you were to take your Prius, with a national average cost of fuel at $2.40/gal, it would cost you about $127 for the whole trip. Normally, this is a plus for the car argument—at $223 cheaper, but these days the race is even. For the sake of competition and to follow the anti-trust laws imposed by the US government, we won’t think about meals, hotels, and other necessary expenditures during your road trip.

We’re all familiar with the concept of miles per gallon but most of us don’t really know how that translates to carbon emissions and your own environmental footprint. On average, planes will emit 53 pounds of carbon dioxide per mile. (I apologize for the number of times the number 53 has appeared in this newsletter; it’s purely a coincidence). The Prius, on the other hand, spits out 0.5 pounds of carbon dioxide per mile. Here we see a similar scale factor to our mpg comparison. The Prius, per mile, is about 100 times better, but because the plane can carry up to 200 times more people, the plane wins out. (per person carbon emissions of ~0.3 pounds per mile) To put this into context, according to carbonfootprint.com, you are personally responsible for 0.29 tonnes, or 640 pounds, of carbon dioxide during this flight—compared to the 1,400 pounds from driving. That’s definitely a lot, unfortunately, so I’m proud of you for being cognizant of this. We all have a personal responsibility to reduce our carbon footprint. While I have you, though, I’ll make you feel a little bit better about yourself. Exxon, the largest energy company in the world, produced 528 million tonnes of carbon dioxide equivalent in 2019. TONNES. That’s 1.2 trillion pounds. In other words, you would have to fly from JFK to LAX all day every day for 1.35 million years to be personally responsible for the amount of carbon Exxon emitted in a single year. Cough cough, something about renewable energy and how large energy companies created the idea of personal carbon footprints to deflect accountability from themselves, cough.

Anyways! What if you took a Tesla? All electric means you spend a lot more time recharging but you’re also responsible for a lot less carbon dioxide. Unfortunately, even though the car isn’t emitting, the sources that power Tesla charging stations often do. Tesla does a good job of using solar for their chargers, but those aren’t always feasible. As a result, the average Tesla emits about 80 grams per mile (0.18 pounds). This means that the same trip in a Tesla puts you at 504 pounds of carbon dioxide. This officially puts you under the plane in carbon emissions, which came in at 640 pounds. Teslas aren’t all neutral but they’re definitely a step in the right direction.

I apologize that this took a detour from purely aerospace subjects, but it gives me a wonderful segue (I know, absolutely ridiculous that this is the proper spelling) into the world of wind and hydroelectric power as forms of alternative energy. Look out for this in a future letter. Okay now you can click the buttons. Thank you for reading!

It's Not Rocket Science

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