"We have a billionaire battle we don't talk about enough. Carl Icahn, when he sold the stock, he really made it clear that Apple's best days were behind it and they had problems with China. Buffett clearly did not believe that scenario," Cramer said on "Squawk on the Street."
When asked what he thought about Icahn's comment, Cramer said, "I do have to say that when you say that China was the problem, you got mainland China. Mainland China is very strong for Apple."
Cramer's comment came after Buffett's Berkshire Hathaway nearly quadrupled its stake in Apple and increased its stake sevenfold in the four biggest U.S. airlines, according to a fourth quarter regulatory released on Tuesday.
Cramer said that perhaps Buffett "got in on another wave of when the Street was believing that perhaps that airlines are no good again."
Assuming Berkshire has not sold its stake, Apple's 16.6 percent stock price gain this year would leave it with a $1.1 billion paper profit in 2017 alone, according to Reuters.
Separately, Buffett revealed last month that he beefed up his stock portfolio at Berkshire Hathaway after Donald Trump's election.
In an interview with talk show host Charlie Rose that aired last month, Buffett said, "We've, net, bought $12 billion of common stocks since the election."
Buffett added it was "in large part" his decision.
Disclosure: Jim Cramer's charitable trust owns shares of Apple.