(CNN) -- The pilot vaunted for his grace under pressure as he landed an airliner in the Hudson River called President Donald Trump "completely unfit" for office and urged people to "vote him out" in response to a report in The Atlantic magazine that the President disparaged US service members killed in battle and chose to skip a ceremony honoring veterans.
Capt. Chesley "Sully" Sullenberger III, whose heroic deed in 2009 came to be known as the "Miracle on the Hudson," unleashed a series of social media posts Friday criticizing Trump and linking to the article, which the President has angrily denied and called "a disgraceful situation."
Later Saturday, a former senior administration official confirmed to CNN that Trump referred to fallen US service members at the Aisne-Marne cemetery in crude and derogatory terms during the November 2018 trip to France to commemorate the 100th anniversary of the end of World War I.
The former official, who declined to be named, largely confirmed reporting from Jeffrey Goldberg in The Atlantic magazine.
Fox News, the Associated Press, the New York Times and the Washington Post have also corroborated various parts of The Atlantic's reporting.
"For the first time in American history, a president has repeatedly shown utter and vulgar contempt and disrespect for those who have served and died serving our country," Sullenberger wrote on Facebook.
"While I am not surprised, I am disgusted by the current occupant of the Oval Office. He has repeatedly and consistently shown himself to be completely unfit for and to have no respect for the office he holds," he added.
Sullenberger, a retired Air Force fighter pilot, wrote that he and his father volunteered for military service in wartime and "that serving a cause greater than oneself is the highest calling, whether in the military or in civilian life."
Sullenberger has always "tried to be a voice of reason and to speak in a measured way," but he felt that he had to call out the President's behavior, he wrote. Trump has "completely failed" to uphold his oath of office and "he has admitted that he cannot comprehend the concept of service above self," the pilot wrote.
"He cannot understand selflessness because he is selfish. He cannot conceive of courage because he is a coward. He cannot feel duty because he is disloyal," Sullenberger wrote.
He concluded his post by arguing that "we owe it not only to those who have served and sacrificed for our nation, but to ourselves and to succeeding generations to vote him out." He posted similar comments to Twitter.
Sullenberger became famous for his calm valor in 2009 as he successfully landed US Airways Flight 1549 in the Hudson River in New York after its engines were knocked out by birds shortly after taking off from LaGuardia Airport. All 155 people on board survived, and Tom Hanks went on to portray the quiet, humble pilot in the 2016 film "Sully."
Sullenberger, a graduate of the US Air Force Academy, retired from US Airways in 2010 after 30 years with the airline and served as an aviation safety expert for CBS News from 2011 to 2017. US Airways had its final flight in 2015 after it merged with American Airlines.
This story has been updated with additional developments on Saturday.