Michael: "Remember what John and Paul said." Frank Quinlan: "The apostles?" Michael: "No, the Beatles. All you need is love." Paul wasn't one of the twelve apostles. While Paul was not one of the original 12 apostles, he was later commissioned by Christ to be an apostle to the Gentiles.
When Michael is dancing in the nightclub, wearing a trench-coat, he spins around in a circle and his trench-coat floats up a little, and there are no wings available, but then immediately following the spin, his wing tips are sticking out from the bottom of the trench-coat.
When Michael is in the field after Sparky has been run down by a truck and he is facing Dorothy, Frank and Huey, the sun is on right hand side and is bright. When the shot goes back to the other characters, they are facing Michael and the sun is also on their right hand side and is obviously lower in the sky.
When all of them are driving to downtown Chicago to see the Sears Tower, there's a shot of the car driving down the highway. Then in the next scene you see them driving down another highway with the lake on the left, and the John Hancock Tower in front of them. This is impossible because the first highway is I-90 and the other highway is Lake Shore Drive (U.S. Route 41). There is no direct way to go from I-90 to U.S. 41. Actually, I-90 and U.S. 41 meet in Northern Indiana, but this would be a circuitous route and if 41 was taken from Indiana, Lake Michigan would be on the right, going to the Sear's Tower.
When the group first leaves Pansy's house, and they're driving down the highway on their way back to Chicago, the rear-view mirror appears and disappears, depending on the shot. Views from inside the car show the mirror. Views looking in from the outside reveal the mirror is missing.
At Joe's, the first restaurant the group stops at, the waitress brings the food and, within minutes, when Micheal gets up to dance, the waitress comes back and takes Dorothy's plate without her having eaten anything from it. The waitress then sets down a cup of coffee.