New Solutions for a Sustainable Future

Cleaner jet fuels are relatively new and lots of research has been done to analyze best practices. Much has been achieved, however by creating consumer access we aim to make these solutions more viable. You join our journey by making your flight carbon neutral and contributing to the future of sustainable air travel.


Flightnook wants to contribute as much as possible to environmentally friendly air travel.We matchmake individuals and organizations to local clean fuel producers.

We raise awareness on air travel’s climate impact, encouraging fliers to understand their flight’s carbon footprint and act on it. Our highest priority is transparency, allowing passengers to understand the benefits of participation.

Flightnook works between passengers and fuel producers, and airlines. We coordinate so your environmental action has a direct impact on industry.

Calculate your individual flight’s emissions and choose a premium. Your contribution replaces fossil based (conventional) jet fuel with cleaner jet fuel. Flightnook chooses producers closest to an airport to keep carbon impact low. Clean jet fuel providers are certified by rigorous sustainability auditors to ensure processes are low-carbon and don’t have negative indirect effects.

Then we send you information about your impact and the collective impact of the #consciousflyer community.

Our calculator offers you the chance to be 100% carbon neutral through cleaner jet fuel or tree offsets.

For cleaner fuel the carbon neutrality is indirect and happens immediately.

This cleaner fuel that burns in flight pollutes 80% less CO2 than fossil fuels on a lifecycle assessment. This is because 80% of the CO2 emissions produced during your flight have been already reduced during previous stages of fuel production. We add a factor to calculate your seat’s emissions to make your flight 100% carbon neutral.

With trees the carbon neutrality is direct, but it takes twenty years. You plant the amount of trees it would take to sequester your flight’s carbon footprint.

The lifecycle assessment boundary is drawn at cleaner jet fuel. Airports and airplane manufacturers enforce their own regulations to ensure the sustainability of their services.

Cleaner jet fuels are the best and fastest way to improve aviation’s climate impact in the next decades. They decrease reliance on fossil-based fuels and are supported by existing airport infrastructure.

Industry is developing more energy-efficient propulsion systems, new lightweight designs, and flexible navigation systems to cut aviation’s carbon cost. But these changes will take at least another decade to become mature and safe, plus it will take time for manufacturers to replace existing airplanes.

Cleaner jet fuels are available today, can be produced sustainably and reduce radiative forcing. We only support rigorously certified second generation cleaner fuels or later (those that don’t compete with food and feed!).

Flightnook is committed to solutions that remain sustainable when scaled. We will never promote fuel alternatives that have negative carbon impacts through indirect land use, like palm oil or those that compete with food and feed.

Depending on the scope of passenger contribution the cleaner jet fuel source might vary, however, it will be certified by or conform to a standard like Roundtable for Sustainable Biomaterials (RSB), US Renewable Fuel Standard (RFS), California Low-Carbon Fuel Standard (LCFS), International Sustainability and Carbon Certification (ISCC), or Renewable Energy Directive (Red II). This means they comply with rigorous sustainability criteria and minimal or zero risk of indirect impacts – such as deforestation or increased food prices.

Each step of the clean jet fuel lifecycle assessment is audited by independent certifiers.

Cleaner Jet Fuels

The most common cleaner jet fuels are made from used cooking oil, vegetable oil, and animal fats. For example, ethanol was primarily made from fermenting starchy or sugary crops, but is now made from cellulosic sources like end-of-life products including crop residues or wood waste.

Once these cleaner jet fuels are processed, blended, and certified by domestic and international standards they can be used for flight.

The cleaner fuels Flightnook utilizes are drop in fuels that can be blended with fossil based fuels without requiring any technical modification of the airplane propulsion system. They fulfill similar chemical and physical requirements as conventional jet fuels and are certified with the same strict standards to be eligible to operate in regional and international passenger air transportation.

At present, the maximum blending volume of cleaner jet fuels is 50% and significant experience has been acquired through experimental and commercial flights. With the advancement of the sector, 100% cleaner jet fuels blends will be available in the future.

There are two types of certifications:

1) Technical certification, which ensures that the fuel complies with the required characteristics for use in current airplanes. Existing technical specifications for cleaner jet fuels are ASTM D-7566, the U.K. Defense Standard (DEF STAN) 91-091 Issue 9, the Brazilian ANP Resolution 63/207, and the Chinese CTSO-2C701.

2) Sustainability certification, which ensures that a given cleaner jet fuel complies with defined sustainability criteria. Some regulatory standards comprise of the US Renewable Fuel Standard (RFS), California Low-Carbon Fuel Standard (LCFS), International Sustainability and Carbon Certification (ISCC), Renewable Energy Directive (Red II), and Roundtable for Sustainable Biomaterials (RSB).

Aviation fuel has a maximum blending volume of 50% clean jet fuels. This mix has been vetted through several pilot and commercial flights. 

Flightnook is pushing towards a future with 100% cleaner jet fuels. 

When compared to fossil fuels, clean jet fuels produce up to 80% less greenhouse gas emissions over a lifecycle assessment. Flightnook promotes clean jet fuels that have a greenhouse gas emissions saving capacity of minimum 50%

Clean jet fuels made from feedstock, like biomass, have already pulled carbon out of the air. So during lifecycle phases of obtaining, refining, and processing they are considered carbon negative. After combustion they are considered carbon neutral because the carbon released is  reabsorbed by another batch of the organic feedstock.  

Once blended with conventional jet fuels, cleaner jet fuels burn cleaner, and they cut radiative forcing by an estimated 21% in-flight.

Clean jet fuels are around twice the price of conventional jet fuel, kerosene. Of course, the exact price difference varies depending on oil price fluctuation and different cleaner jet fuel feedstocks.

The value chain for cleaner jet fuel is relatively new, and requires further logistics to improve. Its limited production blocks it from ramping up and lowering market prices.

Flightnook supports cleaner jet fuel production so this green energy becomes more widely adopted.


Carbon offsets are certifications that commit to an act that reduces greenhouse gases in another location, e.g via tree planting.The amount of trees planted will suck as much carbon dioxide out of the air in the next 20 years as the user pays for. Look at it as an environmental credit card.

The challenge with offsets is ensuring their permanence, additionality, and no leakage. Permanence ensures that planted trees will be around for the amount of time required to pay the carbon debt. Additionality ensures the trees planted would not have been done so anyway, so there’s no double counting. No leakage ensures the planted trees don’t cause land use shift, which would produce uncounted greenhouse gas emissions.

Greenhouse gases (GHGs) are necessary to keep Earth’s temperature stable. But recently we’ve been emitting GHGs into our atmosphere at an alarming rate, causing CO2 levels to rise by approximately 45% since the 19th century. Prior to this influx the amount of GHGs emitted has been stable for millions of years.

Airplanes emit GHGs like carbon dioxide (CO2), methane, water vapor, and nitrous oxide directly into the levels of our atmosphere that trap heat. The more greenhouse gases accumulate, the more heat stays in the atmosphere, increasing temperatures on Earth’s surface.

Global warming means that the average global temperature rises, causing long term weather patterns to alter. It is one of the main causes of climate change. As people produce greenhouse gases, energy is trapped in the atmosphere and it leaves Earth even more slowly, raising its overall temperature.

The delay between cause and effect in climate change is an estimated 40 years meaning that future generations will suffer the most from today’s pollution. Global warming leads to the melting of glaciers, extreme weather and droughts, seriously harming wildlife.

Earth can’t keep up with environmental changes. Global warming also endangers species, who are likely to disappear in the next few years. Future generations will be negatively impacted by today’s greenhouse gas emissions, with poorer communities suffering most from volatile weather patterns and ecosystem shifts.

Global warming has turned into a vicious cycle and we need to take action quickly. The melting of the polar ice caps caused by the rise in temperature leads to further releasing of methane (GHG) which in turn increases global warming.

Sun rays are called solar radiation. While 26% of solar radiation is reflected back into space by clouds, 19% of it is absorbed by greenhouse gases (GHGs) present in our atmosphere.

The remaining 55% reach Earth and are almost entirely absorbed by its surface.

Solar radiation absorbed by the Earth’s surface is reflected back into space in the form of infrared radiation. This infrared radiation is absorbed by GHGs in the form of heat and only a small portion escapes to space. GHGs then send back infrared radiation to Earth to be subsequently reflected back to the atmosphere.

This cycle keeps repeating until no radiation is left for absorption. Radiative forcing is a key process blocking the escape of infrared radiation from our atmosphere.

Airplane engines produce contrails (white stripes in the sky) caused by water vapor and soot particles. The soot particles cause ice crystals to build that form to cirrus clouds – also called contrail cirrus – these clouds prevent infrared radiation from exiting the atmosphere, resulting in a greater net warming effect on Earth.

First studies show that cleaner jet fuel blends of 50% can reduce soot particle emissions of an airplane’s engine by 50 to 70% leading to a reduction of ice particles and therefore global warming.

Aviation has an outsized climate impact on our environment, accounting for an estimated 5% of our man-made climate impact. Airplane emissions heat our planet in three ways:

  • Kerosene jet fuel combustion releases CO2 emissions.
  • Airplanes produce greenhouse gases like nitrogen oxides and water vapor which leave contrails in the sky. These contrails block Earth’s radiation and redirect it to the ground, causing temperature change at lower atmospheric levels. This is called radiative forcing.
  • When contrails linger they become cirrus clouds which intensify radiative forcing.

We account for radiative forcing and other non-CO2 emissions when we calculate your impact through carbon dioxide equivalents (CO2eq).

Both the Kyoto Protocol and the Paris agreement aim to reach the same goal: restrict the global temperature rise below 3.6°F (2°C). However, they do not have the exact same approach in the way they push countries to action.

On one hand, the Kyoto Protocol only focuses on developed countries’ emission levels and has set a fixed target for them to achieve. On the other hand, the Paris agreement made all nations, developed and developing, commit on their own domestic emission reduction targets. While the Kyoto Protocol follows more of a top-down approach by starting with the big picture, the Paris agreement follows a bottom-up approach by piecing things together in order to attain a bigger goal.

During the 2015 climate change conference in Paris (COP21), participating countries agreed to reduce greenhouse gas (GHG) emissions with the goal of keeping the average temperature increase below 3.6°F (2°C) by 2050, compared to pre-industrial levels. 

An average person emits approximately 5 tons CO2eq (GHG emissions translated to a carbon dioxide equivalent value). However, this average value differs significantly between countries.

For instance, emissions for a person from North America, Europe, or Australia are between 10-25 tons CO2eq. To reach the 3.6°F (2°C) temperature goal by 2050, per capita emissions have to reduce to 2.3 tons CO2eq by this year. 

Reducing emissions is a long process that requires immediate action. No other human activity increases individual emission levels as fast as air travel.