Just out of curiosity, which celebrities are we talking about? Several people reference celebrities who lecture (I presume not actually lecture professionally, but talk about) the impact of flying and who themselves fly for leisure.
I can't think of any.
A quick google produced this. There are more but this will do to be going on with:
Elon Musk has been preaching to the world about the harms of carbon emissions. He also travels the world using his Gulfstream G650ER private jet, which uses 1,854 litres of petrol every hour
Leonardo DiCaprio called for emergency actions against climate change. So much so, that in his attempt to fight climate change, he once flew
8,000 miles by a private jet from Cannes to New York City to pick up an environmental award
After telling the world that taking bold action on climate change is the right thing to do for the people of the planet, Richard Branson’s main vehicles for luxury travel are his Dassault Falcon 50 EX private jet and Necker Belle yacht
Arnold Schwarzenegger
After winning his International Climate Leadership Award in 2009, Arnie told us about his vision to fight climate change by passing a new law while Governor of California that rolled back emissions by 25% and approving a multimillion-dollar solar roof initiative. His most fuel-sapping vehicles include a Bugatti Veyron Vitesse, military-grade Hummer H1 and his Gulfstream III
Although Alexandria Ocasio-Cortez infamously claimed that "the world is going to end in 12 years" in Jan. 2019, the New York Post noted that she logged in 66 airline transactions for her 2018 campaign with only 18 Amtrak uses