Plot hole: At the end of the film Woody shows what a nice chap he is by spending the 'tainted' million dollars at a charity auction. He's just made his problems much worse - he paid his solicitor a large fee to arrange the deal, so he hasn't got a million in the bank. That cheque is going to bounce so fast it will crack the plaster on the roof of the bank, and bouncing a million dollar cheque is a serious criminal offence in the US. (There is no way enough interest could have built up to cover the difference, either).
Plot hole: Darby goes to great pains to get out of the country, to where no one will know where she is but Grantham. But upon reaching her "secret" destination, a van pulls up to the plane and a man gets out and hands them an envelope with a copy of the front page of the Washington Hearld with their breaking story and both their names as by-lines. That couldn't happen unless other people besides Grantham and the pilots knew her destination.
Plot hole: When it's learned that Jonah has taken a flight to New York by himself, the panicked adults never think to contact United Airlines, the New York Police Department, port authorities, airport security, the taxi companies, or the Empire State Building staff to alert them that an unaccompanied minor child is headed their way. Instead, Sam hops on the next flight to NYC to search for Jonah by himself. Considering the many hours Jonah waits on the Empire observation deck alone, it is apparent that none of the above knew he was there.