VBA code needed for mandatory cell input based on if please

I want to create a VBA macro which indicates the mandatory column to fill in based on a selected cell . Either Door or Either Airport.

https://ibb.co/coVNey

but if i Extend the range from (E3:E15) for instance i get run time error "13" Type mismatch.

Can anyone help and add it with the airport if statement?

thanks,