President Donald Trump — whose airline, Trump Shuttle, was famously a lemon — once lectured Richard Branson on the airline business.

In a 2004 letter, Trump wrote to the Virgin founder — then hosting an “Apprentice”-style reality show, “The Rebel Billionaire” — saying he should ditch his nascent TV career and “concentrate on your airline, which I am sure, needs every ounce of your energy. It is obviously a terrible business and I can’t imagine, with fuel prices, etc., that you can be doing any better in it than anyone else.”

Branson’s longtime publicist posted the letter on her Facebook page this week. “Like television, you should try and get out of the airline business too, as soon as possible,” the future POTUS — who seems to have been irked by remarks Branson had made about “The Apprentice” — added.

Trump, of course, owned his airline from 1989 until its demise in 1992. Branson, meanwhile, founded Virgin Atlantic in 1984, and it continues to operate today. However, it recently has been ailing because of the coronavirus shutdown: Last month, Branson said he would use his private Caribbean island as collateral to save the airline from collapse.