Biokerosen is made from cooking oil in restaurants, the procedure based only on recycling of burned oil. It does not seem to affect the quality of the flights, but has the advantage of reducing carbon emissions by up to 80%.
In 2011, the Dutch company made its first flight with a biokerosen fueled airplane produced from recycled oil between Amsterdam and Paris and in 2012 made the first intercontinental flight to Rio de Janeiro, marking the longest flight made by airplane biofuel.
Starting in 2013, KLM has started to use 75% of its fuel for airplanes for its transatlantic flights and 25% for cooking oil, according to the BBC.
KLM recorded a record of 34.1 million passengers in 2018, offering its passengers direct flights to 162 destinations with a modern fleet of over 214 aircraft. The airline has over 33,000 employees worldwide.