Statewide Prohibition, enacted in 1914, closed Georgetown's brewing industry, but the district remained a growing industrial and transportation center for Seattle. Straightening and deepening of the Duwamish waterway completed in 1916 made it more accessible for maritime commerce, bringing more waterfront business to the area. A meander loop of the Duwamish through the center of Georgetown was cut off and filled; the old channel and interior of the loop became a new warehouse district served by rail spurs. The Duwamish waterway attracted the Boeing Company, who set up shop in a former shipyard across the Duwamish from Georgetown to manufacture seaplanes. Boeing expanded through the 1920s; its land plane testing airstrip in a field south of Georgetown became a public airport in 1928 and Boeing constructed a new aircraft assembly plant west of the airport in the mid-1930s. The main north-south automotive route through the Puget Sound region was established through the western part of Georgetown in 1928.