UA and AC have exactly the same YQ as LHG from the USA to Europe (in fact they operate together), they just don't pass them along to any FFP. LO and SK also have significant YQ but don't pass them on as well, as the other airlines in my list. Just check the YQ on ITA Matrix for any of these airlines from the US to Europe. The only star airline that I saw that has significantly lower YQ from the US to Europe is Turkish.