After the montage of Jack at basic training, he drops into his bunk with his head opposite the barracks wall. But when George Jr. finds him, his head is next to the wall.
Jack should have had a regulation haircut.
At about the 51 minute mark, after Mildred Dunnock gets up to leave the table, a fly can be seen fly in front of Dorothy McGuire in her reaction shot.
At the bar, Mr. Kress calls the radio a wonderful invention because news travels on it at "the speed of sound". Radio waves travel at the speed of light, not sound.