More likely than an allegation, Buffett was lucky enough to in fact be a pilot and owned a Grumman Widgeon seaplane[1] until he was lucky enough to survive abruptly decommissioning the plane[2] in 1994.

1 https://en.wikipedia.org/wiki/Grumman_G-44_Widgeon 2 https://www.accidents.app/summaries/accident/20001206X01974