Plot hole: At the end of the film Mardukas reveals that he has been wearing a body belt packed with cash - "in the neighbourhood of three hundred thousand dollars" - ever since Jack detained him in New York. Are we to assume that Jack Walsh, an experienced, hard-bitten ex-police officer, now a bounty hunter who routinely chases down violent and armed bail absconders who would kill him without a second thought, didn't even perform a perfunctory search of Mardukas when he detained him? This man used to work for the Mafia! What if he was carrying a weapon? A body belt with three hundred one thousand dollar bills in it would be uncovered by even the most casual pat down.
Plot hole: When Jack and The Duke are told to leave the plane they are still in New York, they then get train tickets from Grand Central Station, also in New York. Yet somehow the plane they left from is already in Los Angeles before the train leaves the station. How did the plane get from New York to Los Angeles that quickly?