Perhaps you should try some spelling variations:
"aircraft production" » "craft production", "aircraft induction", "aircraft propulsion"
"aircraft position" » "aircraft motion", "aircraft piston", "aircraft collision"
"aircraft pilot" » "aircraft pilots", "aircraft piston"
"aircraft pitch" » "aircraft piston"

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (("aircraft pilot") OR ((("aircraft pitch") OR ((("aircraft position") OR ("aircraft production"))))))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"aircraft pilot\") or (((\"aircraft pitch\") or (((\"aircraft position\") OR (\"aircraft production\"))))))*".
• Removing quotes may allow a broader search: (( aircraft pilot ) or ((( aircraft pitch ) or ((( aircraft position ) OR ( aircraft production ))))))*.