When Spencer and Jillian are at the cocktail reception in New York, Jillian is speaking with the rude woman who criticizes her clothes. As they are walking, they walk past a woman with a large pearl necklace who then kisses the gentleman she is with. Moments later, Jillian walks past the same woman again.
All NASA shuttle astronauts live and work in the vicinity of the Johnson Space Center in Houston, many of them in Clear Lake, a Houston suburb. Yet in the film, Jillian teaches school in Florida, where she and Armacost clearly live. Astronauts only go to Florida for launches.
When examining Reese's things, Jillian comes across a Newsweek magazine with a cover story of the accident in space and a cover picture of a B-58. There is no conceivable explanation nor storyline of why a front line story would use a picture of an aircraft retired practically 30 years before the mission.
When Jill is being examined, she is told she is nine weeks pregnant. However, the baby shown on the ultrasound scan screen is clearly much more than nine weeks old. Furthermore the movements of the ultrasound probe do not correspond to the movements on the screen. And when the doctor says she will make measurements she never does. Instead she just waits a few seconds before announcing the age of the fetus.
Toward the end of the movie when Spencer follows Jillian to their apartment, she locks the door and engages the deadbolt. Moments later Spencer is seen trying to get in, screaming for her and banging on the door, until he finally breaks the door open. In a previous scene when Spencer finds Jillian in the bathroom about to take the abortion pills, she tries to escape from him and runs through the hallway only to find him, to her surprise, waiting for her in the entryway which he could only have been accessed through the same way she just came, implying that he teleported or walked through the walls, which he could have easily done when he was trying to get into the apartment.
The goof item below may give away important plot points.
Incorrectly regarded as goofs
At the end of the movie, when Jill is talking to her new husband, he calls her Susan. This is due to the fact that she probably changed her name after Spencer's death (she also seems to have changed her appearance).