The History of Aero - the Milk Chocolate that’s ‘DIFFERENT’

Aero Bar Logo

"Commercial success needs products, or services that differ from, or are superior to competition in some way meaningful and desirable to a worthwhile number of customers" - Dr Ralph Kaner, former Director, Rowntree & Co. Ltd.

Rowntree launched the Aero bar in 1935 with the aim of wrestling a share of milk chocolate block sales from the rival Cadbury's Dairy Milk. Despite having many products on sale, after the First World War Rowntree had not been performing well. The company’s former Director, Dr Ralph Kaner, states that "in 1920 it employed some 8000 workers – but subsequently progress had stalled, and it was experiencing difficulties both competitively and, consequently, financially. Sales of over £5 million in 1920 were to fall to under £2 million by 1930; on occasion it was a struggle to be able to meet even the dividend on the preference shares … Even the possibility of a merger with Cadbury had been aired in York."

The milk chocolate bar was the major staple of the confectionery market. Cadbury’s Dairy Milk had been launched in 1905, and dominated the milk chocolate sector. David Lamb, former UK Advertising Manager at Rowntree comments that "Cadbury had defined what a milk chocolate bar should be", adding that, "In 1933 Rowntree had introduced the Extra Creamy Milk Chocolate bar, but it was a failure."

Developing the Aero Bar

"The only way to sell goods, apart from inherent quality and value, and adequate consumer testing, is to sell an idea into them." George Harris, 1933, then Rowntree & Co. Marketing Manager and later Chairman 1941-52

From 1933 onwards F.J. Fryer, Senior Board Director, and George Harris, then Marketing Manager for chocolate blocks, worked towards developing a unique milk chocolate bar that could make a dent in Cadbury’s market share. In 1931 Rowntree had already begun working with the American advertising firm J. Walter Thompson (JWT), who placed a strong emphasis on market research. Major success with the launch of the Black Magic assortment in 1933 demonstrated that market research was key to product development, as was the need for a strong brand identity. Coincidentally, with Black Magic eating into the market, a new competitor, American company Mars, launched its eponymous bar in England in 1933. Mars used the same strategy of branding to create successfully strong sales, both for the Mars bar and its successor lines.

Of several new Rowntree chocolate block products tested on consumers by Fryer and Harris, the Aero stood out as being particularly popular. Its patented method of production gave it a bubbly texture that proved to have great appeal and crucially made it different from the solid Dairy Milk chocolate bar. Aero was launched in autumn 1935.

The Medium is the Difference

Aero adverts, both 1937. York Museum Trust (York Castle Museum)
Aero adverts, both 1937. York Museum Trust (York Castle Museum)

Aero adverts, both 1937. York Museum Trust (York Castle Museum)

The Aero advertising campaigns of the 1930s and early 1940s sought to ensure the product’s longevity as a unique yet staple confectionery line. Several early Aero newspaper adverts developed by JWT playfully refer to the creative mediums of drawing and photography. The message of these adverts is that Aero is a special bar, with qualities that are near impossible to represent or find elsewhere. The post-war Aero Girls ‘DIFFERENT’ campaign would engage with the medium of painting in order to relaunch the product after the end of confectionery rationing in the 1950s.

Written by Kerstin Doble


Dr Ralph Kaner (2012) George Harris: Rowntree's Marketing Revolutionary. Talk at Tempest Anderson Hall, York, 11 Dec 2012.

Interview with David Lamb (March 2014), former UK Advertising Manager, Rowntree & Co. Ltd.

Fitzgerald, Robert (2007), Rowntree and the Marketing Revolution, 1862-1969. Cambridge University Press; New Edition (25 Jan 2007)