Hall of Fame quarterback Troy Aikman holds the record for the most passing yards in a Thanksgiving day game. He threw for 455 yards versus the Minnesota Vikings 11/26/1998.
The NFL record for passing yards in a single game is held by Norm Van Brocklin of the Los Angeles Rams who passed for 554 yards in a game against the New York Yanks in 1951.
Ben Roethlisberger 504 yards vs Green Bay 12/20/2009
The Denver Bronco's quarterback who holds the record for the most passing yards in a game was Peyton Manning. He passed the record of Drew Brees
Randall Cuningham vs the Washington Redskins on sept.17 1989