sentences:  In 1980 alone, nearly 400,000 passengers and over 2,300 tons of freight passed through Bristow's Aberdeen terminal.Another key source of business was the provision of training services; in 1961, Bristow Helicopters commenced training of helicopter pilots on behalf of the Royal Navy at Redhill Aerodrome, Surrey; further training contracts were quickly secured from other helicopter operators in India, Australia and New Zealand.By 1970, Bristow had also established a training joint venture in Iran, although this was discontinued after the Iranian Revolution of 1979.