In the singular, it is quite clear that one uses "I" when referring to a third party and oneself, as in:
Bob and I are going to build an aircraft.
However, in the plural, it is a lot less clear. For example, if a group of boy scouts are talking about their next project and want to include an outsider, e.g. Sarah:
Sarah and we are going to build an aircraft.
Or would it be:
Sarah and us are going to build an aircraft.
Or even:
Sarah and ourselves are going to build an aircraft.
Please help as otherwise I'll have to shelve the whole aircraft project.
Best Answer
I don't think anyone would word the sentence in the examples provided. It would be either "Sarah is going to build an aircraft with us." or "We are going to build an aircraft with Sarah."
To answer your question directly, I would assume that "Sarah and we are going to build an aircraft" is correct (if you insist on using that word structure), because if Sarah wasn't there it would be "We are going to build an aircraft"