.AI to .WMF

AppleScript can't do this on its own, but it may be able to drive some other application to do the work.

Graphic Converter, for example, can read and write .WMF files, so that might be a good starting point, although it doesn't list .AI as something it recognizes.

If *.ai is infact an Adobe Illustrator file then you can probably consider it a *.pdf in many cases…