Spotting the tiny Elektra Trainer aircraft from far off was never going to be an easy task.
Despite its bright orange fuselage, the small two-seater airplane was barely visible -- a tiny dark speck against a cloudy sky that was getting darker by the minute.
On top of that, the aircraft's electric engines had ensured an almost silent approach, offering no clues about its position.
Until, all of a sudden, it was there! Members of the E-Flight Challenge team lined up to watch the battery-powered airplane gracefully descend on the island of Norderney, just off the northwest coast of Germany.
The landing, mere minutes before sunset on August 29, marked the end of the E-Flight Challenge 2023, which pitted the battery-powered Elektra Trainer aircraft against a Lucid Motors Air sports car, also electric.
Both the aircraft and the car had departed earlier that day from Gelnhausen, a grass airfield near Frankfurt-am-Main, some 300 kilometers (186 miles) south, in a quest to be the first to reach the island.
The purpose of this stunt, devised by a group of electric mobility enthusiasts, was to showcase the expanding capabilities of this promising and fast-developing technology.
The long road ahead for electric aviation
You could say that the E-Flight Challenge takes its inspiration from the early days of aviation.
From Louis Blériot's hop across the English Channel in 1909 to Charles Lindbergh's famous 1927 transatlantic solo crossing, aviation history has often been made on the back of competitive challenges that were eagerly accepted by daring pioneers.
Fast forward a century, and that spirit of discovery has landed in the field of electric aviation -- a small segment of the industry that is steadily expanding its capabilities.
Electric cars are becoming mainstream across the planet, and in countries such as Norway they already make up a solid majority of new vehicle sales -- but it's a different story in electric aviation.
The energy requirements of even the smallest of aircraft are in an entirely different league compared to cars. Existing battery technology simply hasn't yet reached the energy density levels required to power anything more than the smallest categories of aircraft on a short flight. The Elektra Trainer used in the E-Flight Challenge, for example, can carry a maximum of two people.
The batteries currently on the market simply don't cut it, power-wise. Adding larger battery packs doesn't work in an aircraft -- it would just add a massive weight penalty that could seriously impair the performance.
Even one of the most ambitious electric aircraft developers, Heart Aerospace -- a Swedish startup that has racked up orders and investment from United Airlines and other prominent industry players -- announced in 2022 that it was dropping pure electric propulsion for the aircraft they're developing. This was in order to adopt a hybrid-electric approach that would allow it to develop an airliner for up to 30 seats -- still a minnow by industry standards.
The tech isn't there -- yet
Italy's Tecnam, an aircraft manufacturer that partnered with Rolls-Royce and Norwegian regional airline Widerøe in an electric airliner project in 2021, also announced the suspension of its own electric aircraft project this summer, after three years of research, claiming that battery technology is not yet mature enough.
But a recent raft of announcements -- this time coming from battery developers -- offers solid reasons for hope.
China's CATL, a global leader in battery technology, announced in April 2023 that it had developed a 500 watt-hours--per-kilogram battery, which would represent a significant step forward -- almost double what's currently on the market, which is around 270 watt-hours per kilogram.
This was followed, a few days later by Cuberg, the California-based subsidiary of Swedish battery giant Northvolt, announcing progress in its development of a new generation of lithium-metal batteries which have
been shown in testing to provide 380 watt-hours per kilogram -- a gain of 40%.
The electrification of larger airliners, such as the Airbus A320 and Boeing 737-sized aircraft that conduct most flights nowadays, remains a distant prospect.
Aerospace giants Airbus and Boeing have been looking at other technologies such as hydrogen and sustainable aviation fuels as decarbonizing alternatives, since the idea of a battery-powered large passenger aircraft seems currently unattainable.
"Given all that uncertainty we need to take a portfolio approach, continue development and narrow down the uncertainty. Only then will we be able to decide exactly what solution will be right for which part of the market," Robin Riedel, partner at management consultancy firm McKinsey, tells CNN.
In 2021 Riedel and this team at McKinsey co-authored a study that estimated that 17.4% of global commercial aviation emissions are produced by flights under 600 miles (the figure doesn't include short flights performed by flight schools, light aircraft flights and other forms of private aviation). This is a segment of the industry that could be decarbonized relatively fast with novel forms of propulsion that are already available, including hybrid-electric, battery-electric and hydrogen-fuel-cell electric planes.
The advantages would not be just environmental. Since electric motors have fewer moving parts than fossil fuel ones, proponents of electric aviation are confident that, once the range problem is sorted, the lower maintenance and operational costs of electric aircraft will entice operators to make the switch.
Looking to the future
One of the companies that is eagerly awaiting the arrival of electric aircraft is Berlin-based private aviation operator Air2E, which supported the E-Flight Challenge. Its founder and CEO, Norbert Werle, likes to draw a parallel with the early years of electric cars.
"Before Tesla became the household name that it is now, it released the Roadster, which was not exactly a success, but this opened the road. It showed it was possible to make cool electric cars," he says.
Werle hopes that if electric aircraft deliver on cost reductions, they will also absorb some of the traffic that currently moves by road.
This is the assumption upon which some entrepreneurs are building the business cases for new electric-powered regional air mobility businesses.
One of them is Electra.aero, which is developing a hybrid-electric short takeoff and landing aircraft (eSTOL -- STOL aircraft are capable of using very short runways) with the capacity to transport nine passengers or 2,500 lbs of cargo for distances of up to 500 miles. The rationale to develop this type of aircraft is that its lower operational and environmental cost will open up many routes that today are not economically viable, by connecting thousands of underused airfields across the US and other countries.
The Virginia-based firm, however, remains cautious about all-electric aircraft and has opted for hybrid-electric technology combining fuel with an electric powertrain, just like a hybrid car. It considers that only hybrid technology is capable of offering energy densities closer to those of the turboprop aircraft already operated by many regional airlines.
"Aircraft that use only batteries are just not a viable solution for these missions in the foreseeable future. Even with the recent advances, it is likely to be decades before battery technology achieves the energy density it needs in order to be used in commercially viable battery-only aircraft," says founder and CEO, John Langford.
"It took the automotive industry 15 years to move from viable hybrid-electric to battery-only vehicles, and it is fair to say the aviation industry will take even longer. Hybrid-electric aircraft allow you to make a meaningful step to improve emissions today and can improve as battery technologies evolve."
The day the car beat the plane
In this context, the E-flight Challenge served as an illustration of the challenges of electric flight -- but also of its promise.
While the aircraft would be able to hold a relatively straight course across land and sea to Norderney, the road team were counting on the Lucid Air car's advertised 500-mile range and the absence of speed limits on long stretches of German autobahn.
Range was to be, not entirely unexpectedly, the Achilles heel of the aircraft team.
The Elektra Trainer had to make a pitstop roughly halfway along the route, spending two and a half hours on the ground recharging its batteries at Oerlinghausen airfield. That, ultimately, lost it the race.
Once the car reached the ferry terminal on Germany's northern coast, ready to sail over to the island, it was game over. The Lucid Motors team drove into Norderney airport at 6.13 p.m. local time -- seven hours after they had started. The aircraft arrived about an hour later.
Far from being disappointed, though, the organizers were exultant. Who got there first was, ultimately, a secondary matter.
"The accomplishment was to prove that it is feasible to perform such fully electric cross-country flight in just one day. The progress compared to just three years ago has been astonishing!" explains Morell Westermann, one of the E-Flight Challenge initiators.
In 2020, alongside other electric aviation enthusiasts, Westermann completed a record-setting flight from the foothills of the Swiss Alps, all the way to the very same island of Norderney, following a similar route, although flying a different model of electric aircraft. That flight made six world records, including one for the longest distance flown electrically, the fastest average speed over 100 kilometers, the highest altitude and lowest number of stopovers -- all for electric-powered flights.
To put things in context, that flight required three days and 11 re-charging stops to cover the 700-kilometer (435-mile) itinerary, while the 2023 E-Flight Challenge required only one stop for the 300-kilometer journey between the Frankfurt area and the North Sea.
How many stops will the next challenge require we can only guess, but chances are that relentless, incremental advances in the field of electric aviation will keep taking its participants further, faster and, of course, emissions-free.
Westermann, who flies electric planes in his free time, dares to make a prediction: "In 2026, three years from now, technology will be mature enough to fly this distance in just one go!"