Adding extra weight on aeroplanes by filling all aeroplane seats makes the aerodynamics much worse, which increases the emissions of CO2 and other greenhouse gasses. It would be much better for the environment if numerous seats on every aeroplane was left empty, but aviation companies refuse to admit it because leaving empty chairs would decrease their ticket incomes. Because the aviation companies are very powerful and have strong economical self-interest, they are not going to admit it. The only thing people can do about it is buying aviation tickets, travel to the airport and then just go off the aeroplane in the last moment. Because the aviation companies then have got their ticket money anyway so it does not matter a shit for their economical self-interest that some of the passengers go off, people doing so are safe from mysterious deaths and forced disappearance.