At the time, Flynn was a retired lieutenant general and former Defense Intelligence Agency director. He would later become President Donald Trump's campaign advisor and first national security advisor, until he was forced to resign over misstatements about his communications with a Russian diplomat.
Flynn went on a three-day trip with his son, Michael Flynn Jr., staying in a five-star hotel at the Russian government's expense for RT's 10th anniversary celebration in 2015, according to Yahoo. Flynn got nearly $34,000 from the engagement, the report said. In addition, it said, his speaking agency received a 25 percent commission.
Some Democrats allege that Flynn's trip appeared to run afoul of rules barring former military officers from accepting consulting fees, gifts or travel expenses from a foreign government, Yahoo said. It also raises questions about what Trump knew about Flynn's Russian connections before hiring him.
Flynn was fired from the national security advisor role last month following revelations that he misled Vice President Mike Pence and other Trump administration officials about his conversations with Sergey Kislyak, the Russian ambassador to the United States. It stemmed from statements about whether the pair talked about sanctions brought by the Obama administration in response to alleged Russian meddling in the 2016 U.S. election.
The intelligence community said in a declassified report that RT was part of Moscow's effort to undermine confidence in the U.S. electoral system.
Flynn did not respond to a request for comment, Yahoo said. CNBC could not locate him.