· 12 min read
Electric vertical take off and landing air taxis dropping into urban vertiports — collectively urban air mobility or UAM — have taken up considerable space in headlines and investment circles, and have collectively lost over $21 billion in market capitalization, 77% of peak. Smart aviation investors and thought leaders are ignoring the Jetsons future that startups and speculators pretend is coming and focus on what electrification will do for the roughly 8,000 smaller, underutilized public airports in North America and Europe alone.
The economics of air travel have changed radically over the past 40 years or so. Jet turbofan engines have become more and more efficient with each passing year, but only when they are flying at 30,000 feet at optimal cruising speed. They’ve become bigger as well, which is why modern jets have two huge engines instead of four smaller ones. Those newest jet engines are 55% efficient at turning Jet A-1 into forward motion, but not when they are taxiing, taking off or landing. When they aren’t flying in optimum conditions, it’s like pouring kerosene on the airport. By comparison, turboprops on 60-120 passenger propeller-driven commuter planes are around 35% efficient at turning aviation fuel into passenger miles.
That has led to the hub and spoke model of aviation with long legs that exists today, and a significant reduction in percentages and absolute terms of commercial aviation in the turboprop space. The vast majority of passenger and freight aviation flies out of under 1% of airports. The 8,000 smaller airports on two big and rich continents are infrastructure begging for a viable business model.
Electric airplanes unlock that infrastructure, and emerging digital air traffic control and autonomous aviation turbocharge it. There’s a disruption coming, but it’s not with electric rotorcraft buzzing over our schools, highways, offices and homes.
That’s the vision of NASA’s Regional Air Mobility study from early in 2021, which draws on cross-industry collaboration and previous economic studies by NASA to find that a 40% reduction in operational costs of airplanes changes the economics of the aviation industry from the bottom up.
That’s the realization of startup founders such as Anders Forslund of Heart Aerospace, and Mesa Airlines, who have put in 200 pre-orders for Heart’s 19 passenger fully electric airplane expected in 2026, and United Airlines with its 100 pre-orders. That’s the vision of co-founders Josef Mouris and Marc-Henry de Jong of ELECTRON Aviation, which is developing a four passenger, one pilot electric airplane for the general commercial aviation space, with a cargo offshoot, also aiming for commercial deliveries in the second half of this decade. (Full disclosure: I’m on the advisory board of ELECTRON).
Forslund, Mouris and de Jong know that the battery energy density we have today is completely suitable for smaller, fully electric commercial aircraft this decade.
However, the three elements that will turn on the afterburners for those 8,000 airports are combinations of technical, regulatory and procedural innovations and transformations. As such, they proceed at different speeds. After speaking with industry experts including Kevin Antcliff, lead author of the NASA report and now lead product designer for Xwing, which is already test flying autonomous small cargo planes, I developed a maturation model that respects the underlying science, economics and speed of transformation.
I roll a couple of things under the electric airplanes heading. As I’ve spoken to aerospace innovators globally and observed electrification of other modes of transportation, the following has become clear.
The first is that most airframes flying today are old, often decades old. They predate sophisticated and cheaply available computational fluid design (CFD) that has enabled significant improvements in aerodynamics with a lower ratio of expensive wind tunnel testing. They predate the advances in composites we take for granted in other domains. They have rivets. They have exhausts sticking out, as well as air intakes. They are lumpy and bumpy and create turbulence that sucks efficiency out of them. They are heavier than what we can build today. Heart, Electron and others are designing new airframes for battery electric weight distributions, but with better aerodynamics, lift to drag ratios and power to weight ratios. That’s going to continue. Airframes are entering a new period of innovation, and while electric rotorcraft are getting headlines, that’s not where the big wins will be.
The second is that battery energy density is only one of the areas of technical innovation around the drivetrain. New chemistries, new form factors and efficiency curves that are driven by ground-based transportation requirements are rapidly improving the engineering optimization space of cost, energy and weight. Current batteries are fit for purpose for 400-500 kilometer trips with 5-19 passengers, and in the coming decades will rapidly become viable for much longer journeys.
In addition to better, cheaper batteries though, there are additional areas that are going to enable planes to fly bit further with the same energy. I’m engaged with a firm, currently in stealth, that has an innovative drive system with 20% greater efficiency than current electric turboprops. Tesla has shown clearly that power management alone, just getting energy from the battery to the motor, has significant opportunities for efficiency improvements, with one over-the-air update giving 10% greater range to owners. Electric drive trains for aircraft are in their infancy compared to Tesla’s matured solution, and so there’s room there as well. And electrification changes the game for propeller design. With 100% torque at 0 RPM, there’s clear potential to change the pitch, size, number and span of propellers to optimize them better for power, efficiency and noise characteristics.
As I was sitting in the passenger seat of the cockpit of a Harbour Air DeHavilland Twin Otter float plane that was flying its regular route to Victoria, BC from Vancouver, BC, recently, I was looking at the aircraft with fresh eyes. I had walked up to the plane and looked at its sheet metal and rivets, and lost count of the aerodynamic drag complexities rapidly. The pilot started the engine and set the RPM to 2,000 with no pitch, the same as if you sat in a car in neutral and revved the engine to 5,000 RPM. Coughs of black smoke were coming from the exhaust that was sticking out of the side of the engine, along with the sickly smell of unburnt Jet A-1. A dance ensued where the pitch and power was increased to taxi, then pitch and power were increased again to accelerate and climb into the air, then pitch, power and RPM were changed again at cruising speed. The dance was reversed for descent and landing.
Modern composite electric aircraft will slip through the air with less drag, and the complexities of pitch may be thrown away completely given the torque advantages of electric motors, just as electric cars have a single gear which covers all speeds. And exhausts and intakes which create their own turbulence will go away as well.
Autonomous flight systems will lag the maturation of electric airplanes to a certain degree, even though as more electronic than physical systems, they have opportunities for iteration and refinement speed that’s beyond that of aircraft themselves. And they are necessary to speed the expansion of regional air mobility. A key limiting factor for an order or two greater magnitude of smaller aircraft is pilots. It’s not a limiting factor for the next decade, as commercial jet pilots have to get experience and air time somewhere, so smaller commercial operations have a steady stream of new pilots. But after that, there would be more airplanes than pilots for them.
This is a somewhat solved problem already, and it’s also an easier problem to solve than autonomous cars in cities. Aircraft taxi at around 30 kilometers per hour. They are never confronted with oncoming ground traffic at closing speeds of over 200 kilometers per hour. They are on highly controlled aprons where the limited number of humans know to watch out for them and don’t jaywalk. Deer don’t run in front of them. There are no drunk drivers. There are no roundabouts, or five way asymmetrical intersections. There is no one texting and driving, at least not more than once. There are no traffic lights or speed limit signs to interpret.
And once airplanes are in the air, there’s precious little around except air. 99% of the time, a flight path is agreed upon, it’s set and it’s executed without having to avoid anything at all. Potential collisions are observable a long time before they occur as air traffic controllers look at vectors, altitudes and velocity on their glowing screens in airport towers, and give planes nudges to avoid each other.
We have autonomous personal drones already. Throw one of a dozen commercially available follow-me sports action drones into the air and then bomb down slopes or hurtle down single track, and they’ll chase you from the angle you requested, all while dodging trees and wires by themselves. Then they’ll fly to where you stop, land and present you with a great Instagram clip.
And we have commercial autonomous heavy drones as well. DroneSeed flies flocks of five 50+ kilogram drones at a time along preset flight paths and out of line of sight with two only two ground operators. They do this to rapidly replant burnt out forest areas in the United States, dropping moss pucks containing seedlings in precalibrated locations to maximize survival and growth.
And obviously we have semi-autonomous military drones, from the USA’s lethal Predators to the smaller Turkish and Ukrainian drones doing so much damage to Russian military equipment at present.
The problem here is less the technology than the problem of gaining regulatory acceptance. At present, regulations all assume that there’s a highly trained, experienced human being sitting in the pilot’s seat of all aircraft. Ground control staff talk verbally to these pilots to give them flight paths through their controlled airspace for takeoffs and landing. Airspace rules clearly articulate which aircraft of which type, from balloons to soaring craft such as the paragliders I’ve flown to rotorcraft to propeller craft to jets, have the right of way and which direction each will turn in when they don’t have the right of way. Those are rules for humans, and pilot error is a great liability cut out for insurers.
The pathway here is the one Xwing is taking, that of smaller cargo craft following low-risk flight paths that avoid schools and densely populated areas. That will eventually gain acceptance and approval from the FAA, EASA and similar global regulatory bodies, and after that it will expand to higher-risk pathways and eventually to passenger planes. That will take time and a lot of air time.
Initially these will be controlled similarly to the way the US controls its global drone fleet, from ground control pods with constant electronic communication to the flying aircraft, and visual feeds back to the control center. One ground crew will be able to oversee several aircraft, and eventually dozens of aircraft. And unlike pilots, they will be able to leave when their shift is over and hop in their electric cars to get home while a new ground crew takes over.
Just as a lot of air force pilots are now sitting in shipping containers at Creech Airforce Base near Las Vegas instead of in the cockpits of jets, a new generation of pilots will be sitting in commercial operations overseeing multiple cargo and passenger planes, potentially thousands of kilometers away.
The last area of innovation is digital air traffic control. At present, there’s a human at the center of air traffic control. They sit in towers at airports, or increasingly in operations centers that are effectively the same but with cheaper locations and more airports under control, they look at radar plots and transponders, and they talk to pilots in English — the mandated air traffic control language globally — to tell them what to do to move through airspace safely. But they expect that there will be pilots sitting in the planes to talk to, and they expect that verbal instructions will suffice.
What happens when there are no pilots in airplanes? Xwing solves this with the ground crew, who talk to the air traffic controller via the aircraft’s radio as if they were sitting in the cockpit, with the air traffic controller none the wiser. When there are a lot more electric aircraft in the air, from smaller delivery drones to two-ton capacity cargo planes to 19 passenger aircraft, air traffic control won’t be able to depend on a few stressed out air traffic controllers.
It will go digital. Every aircraft will have a transponder, as most do today. They’ll be good participants in a digital air traffic control system, communicating their vector, altitude, velocity and flight path regularly. Computer systems will monitor radar and aircraft messages, project potential collisions and times when there will be too many aircraft in the same volume of airspace, inform human air traffic controllers, gain instructions or approval from the human air traffic controller, and send guidance to the autonomous systems in aircraft, who will divert to the new headings, altitude and velocity.
A lot more aircraft under better control, with the same number of humans doing less stressful but equally important work.
Once again, there are systems which already do portions of this. The problem will be regulatory and transformational. Standardizing communications protocols will take time. Gaining approval for human-in-the-loop air traffic control will take time. Rolling this out fully will take over two decades. Air traffic controllers have to be brought along on this journey. I project this will take the longest to be fully mature.
But the journey starts this decade. New airframes designed for current battery energy densities will be certified and flying commercially in five years. Airports are already building massive solar farms on the flat land surrounding their runways, creating the infrastructural conditions for fueling electric planes, not to mention nearby ground fleets. Autonomous startups, some wisely decoupled from military aerospace, some unwisely linked to the military, are flying experimentally today. Standards and technologies extending current virtualized and remote air traffic control are underway.
The cost advantages of 55% fuel efficient turbojets will be under massive strain as the cost of carbon is counted, either through carbon pricing on the current fossil fuels, or more expensive alternatives such as SAF biofuels (my projected fuel replacement winner for harder to electrify segments of aviation for decades to come). As Christenson and Raynor clearly showed, disruptive innovations creep in from the bottom while leaders fight to retain increasingly hard to please customers at the top. Current aviation business models will be transformed from below with significant shifting of volume to smaller public airports serviced by electric aircraft.
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