Consultants hired by the unions representing aircraft engineers have significant concerns about elements of Air New Zealand’s proposal to send heavy engineering work overseas, and say that the union groups’ proposal can save the airline up to $12 million a year and still keep much of the work in New Zealand. Consultants Michael Stiassny and Brendon Gibson of Ferrier Hodgson have assisted the union groups in preparing a proposal, presented to airline managers by workers outside the Air New Zealand head office in downtown Auckland this morning (Thursday).