By repeating fields do you mean a field that is also in another table?
No. I mean in the same table.
In putting all the people in one table, would I then just have the Airplane table connected to the WorkOrder table?
The idea is that you would have one single table for people. The same table would be used to link a person are a client of as a mechanic.
To establish a relationship between tables, you will have to store the primary key from the main table in any related table as a foreign key field.
... So it is driven by the work orders table.
That contradicts what you said was the purpose for the database.
If you described the purpose of the database accurately then:
Since you said "this database is for a client that wants to keep track of the
planes his work repairs". That would mean that the database is driven by the Planes. Works order are just the activity.
I would have to disagree with you that "it is driven by the work orders table."
I do agree that Access is much better for handling this type of data than Excel.
If it were me doing this project, I would never look at the Excel data until I am ready to import data. In a properly design relational; database, it will look nothing like an Excel spreadsheet. The trap with looking at the Excel data is that it may influence you to make bad design decision for your database.
Side note: I can see an Excel (spreadsheet) influence in your current design now. I am not surprised to hear you say that it is a conversion from Excel.