The 39-year-old also shared a graphic detailing the amount of CO2 and methane the planes ejected during his flights.
Fernández-Castaño inevitably faced some backlash, but doubled down on his criticism of Thunberg by comparing the 16-year-old to Hitler and Joseph Stalin.
"So what? Adolf Hitler was @TIME Person of the Year in 1938. So was Stalin, not once but twice," Fernández-Castaño posted.
Previous winners of TIME's Person of the Year include American Presidents Barack Obama and Donald Trump, along with Mark Zuckerberg and Vladimir Putin.
The accolade is awarded annually to a person or group that "for better or for worse … has done the most to influence the events of the year".
Fernández-Castaño has been a professional golfer since 2004, with eight professional wins. He currently resides in Florida in the United States.