SINGAPORE—Embraer has yet to receive a proposal from Boeing for a possible combination of the aircraft manufacturers, Embraer Commercial Aviation CEO John Slattery said. The two companies are still working on “identifying a structure that might work,“ Slattery said at the Singapore Airshow. He declined to identify further details of such a structure. Embraer and Boeing confirmed Dec. 21 they are in talks about combining their businesses. The potential move follows ...