Goofs

Henry's necktie becomes neatly tied between shots when he is on the elevator.

After getting robbed, Henry tells Nancy that he had his credit card hidden in his shoe, then takes it out. She tells him to put it away and he puts it in his jacket pocket. But when they reach the hotel soon after, he takes it out of his shoe again.

Steve Martin arrives at a with his wife at a New York adverting agency for an interview in just the clothes they're wearing but when they enter the board room he's carrying a portfolio of his work.

The clock in the police station runs five minutes fast in close-ups.

When Henry is singing in the shower and 'butt-flossing', it's apparent that he's wearing dark-colored boxer shorts.

When the main characters are driving out of Boston to supposedly head for New York City, they are seen passing over the Longfellow Bridge over the Charles River. This leads to Kendall Square in Cambridge and would be not be an acceptable route. In reality they would have taken I90 (Mass Turnpike) to get to New York and would not have crossed the Charles River until the I95 interchange in Newton.