WASHINGTON (MarketWatch) - Orders for durable U.S. goods fell a seasonally adjusted 2% in August , mostly because of lower bookings for autos and airplanes. That matched the 2 % drop forecast by economists polled by MarketWatch. Orders minus transportation were flat, the Commerce Department said Thursday. Orders for core capital goods - a proxy for business investment - slipped 0.2%. Shipments of core capital goods, a category used to help determine quarterly economic growth, also fell 0.2% in August .