Sustainable Aviation
AeroDelft Conducts First Hydrogen Aircraft Taxi Tests in Netherlands
AeroDelft’s student team completed the first hydrogen-powered aircraft taxi tests at Rotterdam The Hague Airport, advancing sustainable aviation.

This article is based on an official press release from AeroDelft.
In late May 2026, the student-led engineering team AeroDelft achieved a significant milestone in sustainability aviation. According to an official press release from the organization, the team successfully conducted the first-ever taxi tests of a hydrogen-powered aircraft at an operational airport in the Netherlands. The tests took place at Rotterdam The Hague Airport (RTHA) and represent a critical transition from laboratory research to real-world application.
The comprehensive testing phase included hydrogen refueling operations, powertrain evaluations, and active taxi tests using gaseous hydrogen. By executing these procedures in a live commercial airport environment, AeroDelft and its partners gathered essential data on both the aircraft’s technological performance and the operational protocols required to safely handle hydrogen on an active tarmac.
This achievement is the culmination of extensive engineering and preparation. As noted in the team’s announcement, bringing a hydrogen aircraft to an operational airport required rigorous safety analyses, detailed operational planning, and close collaboration among multiple aviation and energy stakeholders.
Advancing Project Phoenix
From Laboratory to Tarmac
AeroDelft, a non-profit foundation run entirely by Delft University of Technology (TU Delft) students, has been developing “Project Phoenix” since 2018. According to supplementary research data, the initiative focuses on converting a Sling 4 airframe into a manned hydrogen-electric aircraft. Industry research highlights that in May 2025, AeroDelft became the first student team globally to test a full liquid hydrogen propulsion system in a lab setting, working alongside the Netherlands Organization for Applied Scientific Research (TNO).
Safety and Operational Planning
Operating an experimental aircraft at a commercial facility demands strict safety measures. According to project data, AeroDelft developed comprehensive risk analyses and an operational taxi test plan. This was achieved in close collaboration with research test pilots Alexander in ‘t Veld and Hans Mulder from TU Delft’s Flight Test Laboratory, ensuring that the live tests at RTHA’s Fieldlab Next Aviation facility met stringent aviation safety standards.
Technical Specifications and Infrastructure
Gaseous vs. Liquid Hydrogen
The recent taxi tests utilized gaseous hydrogen. While AeroDelft’s ultimate objective is to achieve flight using liquid hydrogen, gaseous hydrogen was selected for this phase due to its current technological maturity. Based on technical specifications provided in the research report, the single-seat converted aircraft uses a hydrogen fuel cell that combines hydrogen and oxygen to generate electricity, emitting only water. With a full tank of gaseous hydrogen, the aircraft is projected to have an endurance of approximately 40 minutes.
Transitioning to liquid hydrogen remains the next major technical hurdle. Because liquid hydrogen offers a significantly higher energy density by mass and volume, the team projects that utilizing liquid fuel will extend the aircraft’s flight endurance to approximately two hours. To achieve this, future development will require the integration of a cryogenic storage tank capable of maintaining temperatures at -253 °C, along with a complex distribution system.
The DutcHâ‚‚ Aviation Hub
The successful test campaign was facilitated by the DutcHâ‚‚ Aviation Hub, a collaborative ecosystem coordinated by the Rotterdam The Hague Innovation Airport (RHIA) Foundation and funded by the City of Rotterdam. The AeroDelft press release explicitly thanked partners including TU Delft Aerospace Engineering, RTHA, RHIA, and Air Products Benelux for their roles in turning months of preparation into a successful live test.
Perspectives on Sustainable Aviation
The transition to zero-emission aviation requires proving that new technologies are viable outside of controlled environments. Isha Moharir, Team Manager at AeroDelft, emphasized the importance of real-world testing in public remarks cited by industry reports:
“We want to demonstrate that flying on hydrogen works and that it’s safe in the air and at the airport… We are making absolutely no concessions on safety.”
Moharir further noted that testing at an operational commercial airport yields invaluable insights into the practical steps needed for sustainable aviation. Similarly, Daan van Dijk, an innovator at Rotterdam The Hague Airport, stated that these tests demonstrate tangible progress. According to research summaries, van Dijk highlighted that testing at an active airport is the exact method by which the aviation industry will learn to safely scale hydrogen-powered flight.
AirPro News analysis
We observe that while much of the aerospace sector’s attention has been focused on the in-flight capabilities of hydrogen aircraft, the logistical realities on the ground present an equally formidable challenge. The AeroDelft taxi tests at Rotterdam The Hague Airport serve as a crucial proof-of-concept for bridging the infrastructure gap. Traditional airports are optimized for kerosene; introducing hydrogen requires entirely new storage facilities, mobile refuelers, and emergency response protocols.
Furthermore, the broader hydrogen aviation race is accelerating. While battery-electric aviation propulsion shows promise for short-haul routes, the prohibitive weight of current battery technology limits its application for commercial passenger aviation. Liquid hydrogen presents a highly competitive alternative for longer ranges, provided that the cryogenic and logistical challenges, which initiatives like Project Phoenix are actively addressing, can be resolved at scale.
Frequently Asked Questions
What is Project Phoenix?
Project Phoenix is an initiative launched in 2018 by AeroDelft, a student-led team from TU Delft, aimed at developing a manned hydrogen-electric aircraft by converting a Sling 4 airframe.
Why did AeroDelft use gaseous hydrogen instead of liquid hydrogen for the taxi tests?
Gaseous hydrogen was used because it is currently a more mature and developed technology, allowing the team to safely test the powertrain and airport integration. The ultimate goal remains transitioning to liquid hydrogen for greater flight endurance.
Where did the taxi tests take place?
The tests were conducted at the Fieldlab Next Aviation facility located at Rotterdam The Hague Airport (RTHA) in the Netherlands.
Sources
- AeroDelft Official Press Release
- Supplementary Industry Research Report (Provided Data)
Photo Credit: AeroDelft
Sustainable Aviation
KBR Selected for Asia’s First Ethanol-to-Jet SAF Plant in Singapore
KBR will provide PureSAF technology licensing and FEED services for a 100,000-ton/year SAF facility on Jurong Island, Singapore.

On June 29, 2026, KBR announced its selection by Keppel Ltd. and Aster Chemicals and Energy to provide technology licensing and Front-End Engineering Design (FEED) services for a proposed 100,000-ton-per-year SAF (SAF) facility on Jurong Island, Singapore.
The planned facility is envisioned as Asia’s first commercial-scale ethanol-to-jet (EtJ) SAF plant. According to the KBR press release, the project will utilize the company’s PureSAF technology to produce a 100% drop-in jet fuel, supporting Singapore’s national mandate to increase sustainability usage across the aviation sector.
PureSAF technology and project scope
The Jurong Island facility will leverage PureSAF, a technology originally developed by Swedish Biofuels AB and engineered for commercial-scale production by KBR, which holds the exclusive global license. The process is designed to convert ethanol into aviation fuel that requires no blending with conventional Jet A or Jet A-1 before use.
In a statement accompanying the announcement, KBR President and CEO Stuart Bradie highlighted the system’s flexibility.
“KBR’s PureSAF is a feedstock-flexible, bankable technology that is designed to deliver a 100% drop in jet fuel, ready to power aircraft without blending. We are constantly innovating our SAF solution to make it compatible with feedstock availability in different regions and to enable the aviation industry to transition to low-carbon jet fuel with a cost-optimized approach.”
The FEED study will determine the technical configuration and project capital expenditure required for the facility. The development remains subject to regulatory approvals and a final investment decision (FID) by the project partners.
Aligning with Singapore’s aviation mandates
The selection of KBR follows a January 28, 2026, agreement between Keppel’s Infrastructure Division and Aster to jointly assess the development of the Jurong Island site. Aster operates as a joint venture between Indonesian petrochemical company Chandra Asri and Swiss commodities trader Glencore.
The proposed 100,000-ton annual production capacity aligns directly with targets set by the Civil Aviation Authority of Singapore (CAAS). Starting in 2026, the CAAS mandates a 1% SAF uplift for all departing flights from the country, with a stated goal of increasing that requirement to between 3% and 5% by 2030.
Alongside the SAF plant contract, KBR and Keppel signed a Memorandum of Intent to collaborate on broader energy transition initiatives. The companies plan to explore technologies related to waste-to-energy, plastic recycling, biofuels, and artificial intelligence-driven digitalization.
AirPro News analysis
We view the progression of the Jurong Island project to the FEED stage as a critical indicator of the Asia-Pacific region’s readiness to scale SAF production. While North America and Europe have led early SAF capacity investments, Singapore’s firm regulatory mandate provides the demand certainty required to underwrite commercial-scale facilities in Southeast Asia. The choice of an ethanol-to-jet pathway is particularly notable, as it allows operators to bypass the constrained supply of fats, oils, and greases that limit hydroprocessed esters and fatty acids (HEFA) production volumes. The project’s ultimate realization hinges on the upcoming final investment decision, which will test the commercial viability of the EtJ process in the current economic environment.
Sources: KBR
Photo Credit: KBR
Sustainable Aviation
NGO Coalition Pushes EU to End Aviation ETS Exemption
The SASHA Coalition urges the EU to end its ETS exemption for international flights ahead of the July 2026 legislative review.

A coalition of environmental and industry non-governmental organizations is urging the European Commission to end the European Union Emissions Trading System exemption for international flights, a move proponents estimate could generate €130 billion in carbon market revenues between 2027 and 2035.
In a campaign coordinated by the SASHA Coalition, groups including Opportunity Green, Transport & Environment, and Carbon Market Watch are targeting the upcoming legislative revision of the European Union Emissions Trading System (EU ETS) scheduled for July 2026. The coalition argues that integrating extra-EEA flights into the carbon pricing mechanism is necessary to fund clean aviation technologies, specifically electro-Sustainable Aviation Fuel (eSAF) and Direct Air Capture (DAC) infrastructure.
The financial and environmental cost of the exemption
The European Union initially included aviation in the ETS on January 1, 2012, but introduced a stop-the-clock mechanism exempting extra-EEA flights following international pressure. According to a policy briefing from the SASHA Coalition, this exemption left an estimated 1.1 billion tonnes of carbon dioxide emissions unregulated between 2012 and 2023. The coalition calculates this resulted in €26 billion in uncollected carbon market revenues during that period.
If the exemption is maintained after its scheduled expiration in 2027, the coalition projects that 1.3 billion tonnes of carbon dioxide emissions will go unregulated through 2035. A full-scope ETS could generate an estimated €14 billion in annual revenue for European Union member states by 2030.
Industry perspectives on carbon pricing and CORSIA
The debate centers on the effectiveness of the United Nations Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA). The European Commission is required to assess by mid-2026 whether CORSIA delivers sufficient environmental ambition. Environmental groups argue the UN scheme is structurally unfit because it relies on offsetting rather than absolute emissions reduction and targets only emissions above a high baseline. Conversely, Airlines and industry groups have historically opposed extending the EU ETS to international flights, citing concerns over market distortions, potential violations of international law, and competitive disadvantages for European hubs.
Clean technology providers argue that a strong regulatory framework is required to drive investment. During a June 9, 2026 roundtable event at the European Parliament convened by the SASHA Coalition, NEG8 Carbon Head of Business Development Dr. David Mulrooney emphasized the necessity of the ETS for commercial strategy.
“To answer your question directly: the EU ETS is foundational to our commercial strategy. NEG8 supplies atmospheric CO2 capture. The stronger and more consistent the carbon price signal, the stronger the investment case for the infrastructure we sell into. ETS is not a policy backdrop for us. It is the market mechanism our business is built on,” Mulrooney stated.
Mulrooney advocated for directing ETS revenue into DAC and eSAF to drive down costs, similar to historical cost curves for solar power and batteries. Member of the European Parliament Cynthia Nà Mhurchú also spoke at the event, noting that regulatory certainty is critical for future planning.
AirPro News analysis
The July 2026 review of the EU ETS represents a critical juncture for European aviation policy. We observe that the European Commission is caught between two competing pressures: the mandate to meet aggressive decarbonization targets and the risk of triggering international trade disputes if it unilaterally prices emissions on extra-EEA flights. The SASHA Coalition focus on revenue generation for eSAF and DAC is a strategic pivot, framing the ETS not just as a punitive tax but as a necessary funding mechanism for the aviation industry transition. Overcoming airline opposition to overlapping carbon pricing regimes will require the Commission to clearly articulate how the EU ETS and CORSIA can coexist without creating prohibitive administrative and financial burdens for operators.
Sources: SASHA Coalition
Photo Credit: SASHA Coalition
Sustainable Aviation
Delta Air Lines Installs VCT Finlets on 240 Boeing 737NG Jets
Delta Air Lines will fit aerodynamic finlets from Vortex Control Technologies on 240 Boeing 737-800 and 737-900ER aircraft.

Delta Air Lines will install aerodynamic finlets from Vortex Control Technologies across 240 of its Boeing 737 Next Generation aircraft to reduce drag and lower fuel consumption.
Announced in a company press release on June 17, 2026, the modification program targets the carrier’s Boeing 737-800 and 737-900ER fleets. The installation follows computational fluid dynamics analysis and flight test validation, aligning with Delta’s broader sustainability objectives to address the 90 percent of its carbon footprint generated by jet fuel.
Aerodynamic modifications and fleet implementation
The Vortex Control Technologies (VCT) finlet package consists of small aerodynamic devices installed on the aft fuselage of the aircraft. These structures are designed to reshape airflow around the tail section, reducing flow separation and improving overall pressure distribution. By mitigating aerodynamic drag, the finlets directly decrease the amount of thrust required during cruise, resulting in lower fuel burn.
Delta Air Lines Chief Sustainability Officer Amelia DeLuca stated that the carrier seeks out innovations that reduce environmental impact and generate long-term operational benefits.
“We appreciate the strong partnership with VCT throughout the evaluation process and are looking forward to this implementation to further support our ongoing fleet efficiency initiatives,” DeLuca said.
VCT Chief Executive Officer Gil Morgan noted that equipping the 240 Delta aircraft represents a significant milestone for the manufacturer.
“We are proud to provide a practical technology that helps airlines improve fuel efficiency, reduce carbon emissions and enhance operating economics,” Morgan said.
Regulatory approval and industry adoption
The VCT finlet system operates under a Federal Aviation Administration (FAA) Supplemental Type Certificate (STC). The technology has steadily gained traction among Boeing 737 Next Generation (737NG) operators seeking incremental efficiency improvements. On September 26, 2025, the European Union Aviation Safety Agency (EASA) validated the FAA STC, clearing the devices for installation on European-registered aircraft.
Other operators have also adopted the modification. On July 29, 2025, Avelo Airlines announced a follow-on order for additional VCT finlets. The carrier reported proven fuel savings and emissions reductions after 18 months of in-service performance across its own Boeing 737NG fleet.
AirPro News analysis
We view Delta’s adoption of aft-fuselage finlets as a pragmatic approach to extending the economic viability of its Boeing 737NG fleet. While winglets have long been the industry standard for drag reduction, aft-body modifications represent an incremental but valuable efficiency gain for mature airframes. As airlines manage delayed deliveries of next-generation narrowbody aircraft, retrofitting existing fleets with drag-reducing technology offers an immediate reduction in fuel burn and emissions without requiring significant downtime or capital expenditure.
Sources: Delta News Hub
Photo Credit: Delta Air Lines
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