Booking a Sustainable Flight?
by Fred Horch, Principal Advisor, Sustainable Practice.
All-electric air taxis may start flying in 2025. Will you be hailing one?
In the near future, we’ll fly on sunshine, using electric motors powered by batteries storing solar energy to move people and packages through the air. The “airspace blueprint” for all-electric air taxi service in the United States has been released by the Federal Aviation Administration, with limited operations expected to begin in 2025.
While we’re waiting for our sky taxi, here’s a “sustainable seven” list of practical steps we can take today toward sustainability when we fly:
- For business, fly the virtual skies: Zoom around online rather than on planes.
- Save take-off for trips longer than three hours (or so); travel by ground for shorter trips (until electric airplanes enter short-haul service).
- Walk, cycle, ride public transit, or drive electric to get to and from the airport.
- Pack light to reduce unnecessary weight on the plane.
- Book a direct flight.
- Fly economy, not first class.
- Use a service like Skyscanner to choose flights that emit less pollution.
“Let your fingers do the walking” was a catchy 1970s slogan for the Yellow Pages — urging people to save time and energy looking in the phone book rather than zooming all over town. Now we can Zoom from our room, virtually flying around the world in an instant. Videoconferencing is replacing business travel, with one in three US companies acknowledging the need to reduce travel per employee by more than 20% to meet their 2030 sustainability goals.
Batteries: Making Electric Flight Possible
We’ve had electric cars, trolleys, and trains since the 1800s, but until recently, no electric aircraft because batteries were too bulky and too heavy. New technology changes that: we can now build battery-powered flying machines.
To understand why companies are just starting to build electric airplanes and the FAA is just starting to certify them, consider a crucial difference between batteries and fuel, two ways to store energy. Because they store and release electricity (the most useful form of energy), rechargeable batteries are far superior to fuel for most purposes. But fuel has one advantage — energy density.
The higher the gravimetric density (joules per gram) of energy storage, the lighter the load — a critical factor for practical aviation. Here’s a chart that explains why we haven’t been flying with batteries (or wood or coal, for that matter):
The good news is that battery technology has lots of room to improve!
A lithium-air battery based on lithium oxide formation can theoretically deliver an energy density that is comparable to that of gasoline.
— A room temperature rechargeable Li2O-based lithium-air battery enabled by a solid electrolyte, Science
Better batteries will make long-haul electric trucking and long-haul electric flying cheap and easy.
Before Batteries Get Better
The extremely low energy density of lithium-ion batteries is a hurdle that many companies are jostling to jump over because the rest of the pathway to sustainable aviation is so clear. Once we’re no longer burning fossil fuel, flying will be a fantastic way to move people and packages.
To travel across a continent or between continents, flying is the most time efficient. It also is resource efficient. Using the airports we already have plus a few thousand electric planes that we will start building soon, we can enjoy high-speed, emission-free direct travel anywhere in the world. Electric air taxis will take us from the airport to near our final destination. Sustainable aviation will cost a small fraction of the time and money required to build and maintain high-speed electric rail everywhere.
Some of the steps we can take toward a sustainable aviation future are obvious, but a few are perplexing. Obviously, while our aviation industry is burning fossil fuel, doing more business by phone or videoconference, and less by flying in person, is a good idea — as long as we can be productive working remotely.
Being thoughtful about what we pack is another obvious choice. A 747 jet burns fuel at a rate of about a gallon per second while cruising at 35,000 feet above sea level carrying more than 500 people and their luggage. Imagine if we had to carry our bags up a 35,000-foot stairway! Flying is lifting weight from one place and then carefully setting it down somewhere else. Every bit of weight savings matters: United Airlines made headlines when they saved 643,000 liters of fuel just by using lighter paper for their inflight magazine.
Lifting weight is what uses most of the energy during a flight. That’s why a direct flight is more efficient than several shorter flights. Cruising horizontally requires less energy than climbing. If you’ve ever bicycled, you can relate. How tired do you get going up and down steep hills compared to pedaling along a level road?
Flying instead of driving might save fuel and prevent pollution, depending mostly on passenger load factor — are there empty seats? One jet plane can carry 180 economy passengers, but one economy car can only seat up to five. Not surprisingly, to move 180 people two thousand miles (the distance between Boston and Salt Lake City, for example) it would be better to fly just one jet than drive 180 Toyota Priuses.
When we’re booking a ticket, thanks to services like Skyscanner, it’s now easier to choose more efficient airplanes (which also tend to be more modern and comfortable). Keep an eye out for flights that have fewer emissions. And, of course, the more people per flight, the less impact per person. Flying in economy class is better than first class — for sustainability. Without first class seating, more passengers can fly.
What about the argument that we might as well catch a flight, since the airplane would fly anyway? Or the similar argument that if we didn’t buy a first class ticket, someone else would? Sometimes airlines fly empty planes just to retain airport slots, but more often they cut flights from their schedule if they don’t sell enough tickets. At the end of the day, airlines are in a competitive industry: they can’t keep flying routes or offering roomy first class seating if they don’t have enough paying passengers.
The more perplexing choices are deciding which airlines are the most sustainable and whether to pay for carbon offsets. My advice is to support companies and projects that have a good sustainability story. But know that we can’t “undo” our damage with a carbon offset. Not packing twenty pounds of “just in case” clothes is a better idea than bringing a heavy suitcase and buying a carbon credit to offset our well-deserved guilt. To be really sustainable air travelers, we can budget for a first-class ticket but fly economy and donate the difference to a carbon offset project.
What’s Still Ahead on the Pathway…
Walking, cycling, or riding a micro EV are the most sustainable ways to move, but when we need more speed and protection from the elements, a BEV is a good next step. One day we’ll be able to fly electric. Next we’ll consider public transportation — is there a sustainable future for buses and trains, or will autonomous (self-driving and self-flying) EVs take over?
Once we’ve explored the full pathway to sustainable movement, we’ll start on the related pathway to sustainable energy. As we stop burning fossil fuel to move, what energy sources are we using instead? Stay with us on the journey to sustainability as we take action to have a positive impact on the world.
Questions? Comments?
What have you discovered on the pathway to sustainable movement? What has worked well — and what hasn’t been that great — for you? Share in a comment!
References and Further Reading
- FAA Releases Airspace Blueprint for Air Taxis, Federal Aviation Administration
- This electric flying taxi has been approved for takeoff — sort of, NPR
- Working to Build a Net-Zero Sustainable Aviation System by 2050, FAA
- Air Taxis, Hyped for Years, May Finally Take Off, New York Times
- ‘This Could Have Been a Zoom Meeting’: Companies Rethink Travel, New York Times
- 10 ways you can reduce carbon emissions when you travel, National Geographic
- How to Reduce the Carbon Footprint of Your Travels, Sustainable Travel International
- Electric planes are coming: Short-hop regional flights could be running on batteries in a few years, The Conversation
- Sustainable Air Travel, Mossy Earth
- Millions of cheap flights. One simple search., Skyscanner
- Flashback Friday — “Let your fingers do the walking.”, Baer Performance Marketing
- To Zoom or not to Zoom: The shifting focus of business travel, Innovation Origins
- Navigating toward a new normal: 2023 Deloitte corporate travel study, Deloitte
- The total impracticality of electric aviation, SUAS News
- Alice, the World’s First All-Electric Passenger Jet, Just Aced Her Maiden Flight, Popular Mechanics
- The FAA Has Begun To Recognize Electric Propulsion During Certification, Simple Flying
- A room temperature rechargeable Li2O-based lithium-air battery enabled by a solid electrolyte, Science
- This startup sees a need for aviation-specific batteries, Aerospace America
- Surprising Working From Home Productivity Statistics (2023), ApolloTechnical
- How Much Fuel Does an International Plane Use for a Trip?, How Stuff Works
- Flight Profile, Capital A
- United Airlines saves 643,000 litres of fuel by using lighter paper on inflight magazine, The Sydney Morning Herald
- Thousands of Planes Are Flying Empty and No One Can Stop Them, Wired
- Focus: US airlines thrown a curveball as consumer habits change post-pandemic, Reuters
- Airline Deregulation: When Everything Changed, Smithsonian
- The Last U.S. Airline to Offer First Class Is Getting Rid of It, BestLife
- Global sustainable aviation leaders announced at the CAPA Environmental Sustainability Awards 2022, CAPA
