Rules governing financing backed by export-credit agencies for aircraft purchases are set to change in 2011, making the cost of financing more expensive. The point is to spur activity in the commercial-finance market. Aircraft manufacturers and airlines appear leery of the change. Nigel Taylor, senior vice president of structured finance at Airbus, said the change will make export credit twice as costly. Banks, however, said the change is necessary if more options are to come to market.