When Eko is comforting Ana Lucia at the ravine, he holds her and his left arm is over her left arm. When the camera angle changes, his arm is now under her arm.
When Goodwin and Ana Lucia are taking a break before their fight, the top of a white car is visible driving in between them in the background, from right to left.
Ana Lucia states that they were in the air for two hours, contradicting dialogue from the pilot that it was closer to eight (the last two of which were after changing course).
In the opening scene Ana Lucia performs CPR on a little girl very incorrectly. She places one open-palmed hand on the girl's chest and the other on the girl's forehead. Even though the girl is young, you still use both hands to perform CPR. You just use less pressure than you would for an adult.