Is fasting obligatory for a traveler from Los Angeles to Morocco on the mentioned dates, or is she permitted to break her fast, and can she complete the fast of Monday then break it on the plane?

A traveler is permitted to break their fast and shorten prayers (qasr) once they have passed the inhabited houses of their town. Thus, you are permitted to break your fast on the day of your travel (Monday) after passing the houses of the village or city where you reside. Some scholars hold that it is not permissible for one who travels after dawn to break their fast on that day, but the first opinion is more correct.

You are permitted to break your fast inside the airport if it is outside the town. However, if the airport is within the town, then it is not permissible to break the fast until after the plane takes off.

Based on this, you are permitted to break your fast on the day of travel (Monday), although it is preferable not to break it, to avoid scholarly disagreement.