Given the choice between ‘a guy is lying/mistaken and so are a few others’ and ‘a worldwide conspiracy has existed for 80 years to cover up the existence of ali

Given the choice between ‘a guy is lying/mistaken and so are a few others’ and ‘a worldwide conspiracy has existed for 80 years to cover up the existence of alien visits to Earth’, I’m going to apply Occam’s Razor and go with lying.