Trump probably told them that he would cancel obama idiotic mileage requirement if they considered moving back to the USA.
My take is that we do not want Ford to be 'moving back' because this movement we got is that Ford is growing and "moving back" means it would have to be shrinking. I was just looking at Ford's map of overseas factories and noticed that it's even got two plants several hundred miles east of Moscow!
Ford's big, and we want it to be big and it means we got lots of Americans overseeing ops everywhere.