Plot hole: Will is telling Mac that the DOJ is being out-lawyered by a group of financial institutions, including Lehman and Countrywide, both of whom went out of business in 2008, well before the date of this episode on New Year's Eve 2011.
Continuity mistake: The stock footage of the airplane that Don, Sloan and Elliot are on is of a Boeing 747, a very large widebody plane. However, the internal shots of the plane suggest that it is actually a much smaller narrow body plane. (00:13:55)