• provides expert assistance required by the Assembly, Council, Air Transport Committee (ATC), Committee on Unlawful Interference (UIC), Committee on Joint Support of Air Navigation Services (JSC) and the specialized conference, divisional, panel and working group meetings that may be convened in the air transport field;
• provides economic advice to other bodies and Bureaux of the Organization, particularly the Committee on Aviation Environmental Protection (CAEP), the Air Navigation Bureau (ANB), and the Technical Co-operation Bureau (TCB);
• prepares studies and develops recommendations for policy guidance in the fields concerned;
• prepares procedural documentation concerning amendments to Annexes 9 — Facilitation and 17 — Security to the Convention and the compilation of lists of differences to these Annexes which are notified by Contracting States;
• coordinates and implements a programme of universal, mandatory and regular audits of the aviation security systems in all ICAO Contracting States under the Universal Security Audit Programme (USAP)
• prepares and revises manuals on airport economics, air navigation services economics, economic regulation of international air transport, air traffic forecasting, facilitation, the ICAO statistical programme, and a manual and several Standardized Training Packages (STPs) on aviation security;
• promotes the implementation of ICAO Annexes, policy and guidance material developed under the air transport programme through missions, informal regional meetings and training courses;
• administration of the Joint Financing Agreements with Denmark and Iceland for the provision certain North Atlantic air navigation services (DEN/ICE), of the Arrangement on the Joint Financing of the North Atlantic Height Monitoring System (HMS), and of the Agreement on the Sharing of Costs of the Satellite Distribution System for information relating to Air Navigation (SADIS);
• collects, analyses and disseminates, via the Internet, civil aviation statistics;
• prepares relevant publications (including tariffs for airport and air navigation services) and forecasts;
• prepares Chapter 2 of the Annual Report of the Council and contributes text to the Annual Review published in the ICAO Journal which provides worldwide surveys of international civil aviation developments;
• administers the International Financial Facility for Aviation Safety (IFFAS) which is a mechanism to provide financial support toward achieving the objectives of improving aviation safety through the implementation of the necessary measures mainly identified by the Universal Safety Oversight Audit Programme(USOAP);
• coordinates the ICAO air transport programmes and the work of the African Civil Aviation Commission (AFCAC), the Arab Civil Aviation Commission (ACAC), the European Civil Aviation Conference (ECAC) and the Latin American Civil Aviation Commission (LACAC); and
• provides liaison on air transport programmes with the United Nations and other international organizations (notably with regard to environmental protection, trade in services and facilitation matters) and support for international cooperative projects.

Within this framework, the work of the Air Transport Bureau for the 2007-2009 triennium reflects a significant repositioning, consistent with the Business Plan of the Organization, in response to increasing demand for regulation and monitoring of aviation security worldwide, globalization and transnationalization of markets, the emergence of regional and sub-regional trading and regulatory blocs, liberalization of economic regulation, recognition of and response to environmental concerns, the commercialization of airports and air navigation services providers and application of "user pay" and "polluter pay" principles.

Please visit this link for a more in-depth look at the Air Transport Bureau programmes.