Continuity mistake: On the airplane, when Roy asks Johnny if he knows the flight attendant's name yet, the headset is around Roy's neck, but in the closeup it vanishes, then next shot it reappears again.
Continuity mistake: During Johnny and Roy's flight to LAX there are a few shots of the airplane in mid-air and when it lands, and the type of airplane changes - note the engines and tail.
Continuity mistake: When transporting the heart attack victim from the plane the ambulance starts as a Ford and ends as a Chevy.
Continuity mistake: Marco's mustache goes missing when Station 51 is dispatched to the structure fire, but then it reappears.
Answer: It is standard practice to wet down driveways so that they stand out in a long shot.
stiiggy