In 1946 Normalair Ltd. was formed as a subsidiary company of Westland Aircraft Ltd. to meet the growing demands for this specialist equipment, and today employs 1,100 people and has its own extensive production facilities. Normalair operate the most extensive respiratory laboratory, and are the largest producers of aircraft pressurisation, air conditioning and oxygen breathing equipment, in Europe.

All British military aircraft that are pressurised are fitted with Normalair equipment, and such famous airliners as the Viscount, Britannia and Comet are equipped by Normalair.

With subsidiary companies in Canada and Australia, and with representatives and agencies all over the world, Normalair provides a very wide market with cabin pressure controllers, discharge valves, safety valves, humidifiers, water extractors, flow control valves, cooling turbines, oxygen regulators, liquid oxygen converters, and many items of equipment vital to the needs of the aircraft of today.

For several years the company has had license agreements with the two American companies foremost in these fields, namely the Garratt Corporation of Los Angeles and Bendix Aviation of New York. These agreements have been the source of substantial dollar export business by Normalair.

In 1953, Normalair provided the oxygen equipment that enabled Sir Edmund Hillary and Sherpa Tensing to be the first to conquer Everest and, in 1955, provided the oxygen sets that were used in the first successful assault on Mount Kanchenjunga.

The company also produces lightweight portable oxygen equipment for medical, industrial and emergency use, and are the sales agents in the UK for the respirators and breathing equipment made by Mrs Dräger of Lubeck. This business is handled by Normalair's branch office in Manchester.

The Garrett Corporation took a 48% share in the company in 1966, and was subsequently renamed Normalair-Garrett Limited (NGL). The company is now Honeywell Normalair Garrett Ltd.