Which United Nations organization establishes technical specifications for aviation?

The International Civil Aviation Organization (ICAO) is the United Nations organization specifically tasked with setting global standards and regulations for civil aviation. It plays a crucial role in ensuring safe, efficient, and orderly development of international air transport. ICAO develops technical specifications, known as Annexes, which address various aspects of aviation, including safety, security, air navigation services, and environmental protection.

The other organizations mentioned do not focus on aviation. The World Health Organization (WHO) is concerned with public health issues; the International Maritime Organization (IMO) handles regulations for shipping and maritime safety; and the International Telecommunication Union (ITU) focuses on issues related to telecommunications. None of these organizations establish technical specifications specifically for aviation, highlighting ICAO's unique and critical role in this area.