Continuity mistake: The favorite family restaurant is "Enzo's" and that is the name in neon at the place. But during the confrontation with Nick and Mary in the car (in the rain) Nick says to never go back to "Sorento's." My guess is that they changed the name after filming the scene. (01:05:20)
Continuity mistake: When Cusack is in bed with Thornton's wife, her nipple is covered in half of the shots from the side of the bed, and exposed in the other half.
Continuity mistake: At the beginning of the movie Cusack and Blanchett are having sex. Afterwards Blanchett gets dressed to leave to talk to a teacher of their son and she buttons her blouse wrong. In the next shot however the blouse is buttoned correctly.
Answer: In the film, it's a phrase used to describe the job of an air traffic controller. They're responsible for maneuvering the airplanes around in the skies. "Tin" refers to the airplanes and they're moving, or "pushing", them around. I tried to find if this was a real reference or phrase used in air traffic controllers prior to 1999, or just made up for the movie. It seems it's a phrase made up for the movie (but I can't say for certain as I have no experience in that field).
Bishop73