Purpose – Reach awareness that the aviation industry (manufacturers, airlines, organizations) is lying about cabin ventilation on board of passenger aircraft. --- Approach – Industry information published during the corona pandemic is collected from the Internet and set against scientific evidence. --- Findings – HEPA filters in aircraft do not produce cabin air "as clean as [in] a hospital operating theatre". Viruses and other substances like CO2 are generated in the cabin and need to be washed out. Their concentration follows from their source strength and the ventilation air flow rate. Aircraft cabin air is not "fully renewed in 2 to 3 minutes". It takes several such air changes to reach 1% of the initial concentration. The air change rate is not even relevant for the concentration of e.g. viruses or CO2 in the cabin. The "air flow in the cabin" is not "only flow from top to bottom". The air is mixed within several rows and beyond. --- Research limitations – Neither the industry campaign nor the literature on (aircraft cabin) ventilation is fully explored. Only examples are given to illustrate how the aviation industry deceived politics and the public for their economic advantage. --- Practical implications – Learning from the past to be prepared for similar manipulation in the future. Importance to question any given information – also this one. --- Social implications – The discussion opens up the topic beyond aviation expert circles. --- Originality – Not much comparable information is given by other authors.