 Plant 1 served Boeing well while it was producing seaplanes that could be assembled then launched into the Duwamish Waterway for flight testing.For land planes the process was more cumbersome; airplanes were produced and assembled onsite, taken apart, barged to Boeing Airfield, flight tested, disassembled, and shipped to the buyer.With introduction of larger all-metal airframes by Boeing in the 1930s, the need for a facility dedicated to metal fabrication and assembly with direct access to the airfield became critical for productivity and Plant 2 was opened on the east side of the Duwamish in 1936.