Jeffery Smisek, a former Vinson & Elkins partner serving as CEO of United Continental Holdings Inc., stepped down Tuesday as head of United Airlines’ parent company in connection with a federal corruption investigation involving senior executives at the Port Authority of New York and New Jersey.

One of those executives is David Samson, a high-powered Garden State lawyer who resigned last year as chairman of the Port Authority amid allegations that he used his position to financially benefit Wolff & Samson, a West Orange, New Jersey-based firm where he served as a founding and name partner.