Hall Bartlett's film begins with images of war, fighter planes taking off during World War II. We see Ted Stryker in the cockpit gunning enemy fighters down. But once he is put out of service and hospitalized we see the effects of the war have changed him. Bartlett transitions this soldier home and we see the correlation of his time in war to his home life as he has had a difficult time holding down a job (12 in 10 years) and his marriage is on rocky ground). He finally lands a job, but comes home to find his wife and son have left him.
The rest of the film is about Stryker being the only man who can save the passengers aboard the commercial airliner. It is a disaster waiting to happen, but the metaphor for the storm and the food poisoning is that they are the symptoms of difficult time in the marriage, which is represented by the airplane. And, it is the choice of Stryker and Ellen to fly through the storm in an attempt to land safely (there's no safety guaranteed). Ellen coming into the cockpit to work the radio while Stryker pilots the aircraft is symbolic of the need for them to work together for the sake of the sick passengers, which is the heightened representation of the effect they could have upon Joey, their son if they don't.
Thus, Stryker having to come face to face with the reality of the war he has brought home, and Ellen choosing to believe in her husband even when it seems all is lost, are elements necessary to navigate the stormy circumstances of their marriage. In addition, they are able to land and get everyone, including Joey, to safety. The fact that they crash land is symbolic of the truth: that marriage is difficult, but to go through that kind of experience, together, creates a depth of unity that is harder to break over the long run.