< PrevNext > 6. McKinsey & Co. New York City Share 2017 U.S.-Booked Air Volume: $248 millionConsolidated U.S. TMC: Amex GBTPrivately held management consulting giant McKinsey & Co. spent about $8 million more on U.S.-booked air travel in 2017 than the year prior, according to a BTN estimate. Revenue reached $10 billion, according to the Financial Times, up from about $8.8 billion in 2016. The firm has more than 28,000 employees, about 14,000 of whom are consultants, an increase of about 2,000 consultants from 2016. McKinsey has deployed videoconferencing equipment on a widespread basis to avoid what it deems unnecessary travel.