By 1936 the company felt justified in constructing a large new manufacturing facility in Seamer Road, Scarborough. This allowed increased production, and Plaxtons became popular with many independent operators throughout Northern England. Many of these operators purchased their vehicles through independent dealers, rather than directly from the factory. In this regard, Plaxton's sales were through Lancashire Motor Traders Ltd of Manchester and Arlington Motor Co Ltd of London. The company became known as FW Plaxton & Son by 1937, as the founder's son, also named Frederick William joined the company at the age of 18. FW Plaxton junior was to be known as Eric to avoid confusion with his father.

Plaxtons built a number of different coach designs through the 1930s, until settling on a distinctive house style. The style typically consisted of a very rounded front profile at the windscreen area with side windows that sloped backwards at the front, were upright at the centre, and sloped forward at the back. Bodywork for the Bedford WTB chassis was particularly distinctive, sloping severally from the bottom of the front wheel arch to the roofline, leaving the "bullnose" radiator grille protruding. The rear also sloped prominently. The WTB chassis was very popular choice for operators at that time, together with the Dodge RBF and SBF. Leyland and AEC chassis were also popular for larger coaches, notably the Leyland Tiger and AEC Regal.

On the outbreak of World War II in 1939, coach production halted and the factory was turned into a munitions factory under the control of the Ministry of Aircraft Production. Many records from the early years were lost when an incendiary bomb set fire to the Seamer Road factory in 1943, causing much damage. As the factory was under control of the Ministry of Works, production continued in the open air whilst a replacement was constructed. Some adjacent land was loaned by a market gardener who subsequently joined the board years later.
When and why was the plaxton coach production halted?
Coach production was halted in 1939 due to world war outbreak. The factory was turned into munitions factory.