The International Civil Aviation Organization (ICAO) has nominated 7 states to oversee the provision of air navigation services over the North Atlantic.  These countries are the United Kingdom, Iceland, Canada, Norway, the United States, Denmark and Portugal.

The Icelandic flight information region (FIR) is called BIRD. This FIR, along with the upper flight levels of the Greenlandic Nuuk FIR north of 63˚30"N, spans from 61°N to the North Pole and from 76°W until 30°E and together they make up the Reykjavik Control Area (CTA).  The lower flight level limit of the control area is changeable, from sea level within the BIRD FIR up to 20,000 feet over the Nuuk FIR.  There is no upper flight level limit.

A quarter of all air traffic travelling over the North Atlantic goes through the Reykjavik CTA which is run by Isavia ANS.

Air navigation service provision within the Reykjavik CTA uses flight data provided by radar, ground and space based ADS-B stations.

The Nuuk flight information region extends over all of Greenland up to 19,500 feet.  Isavia ANS provides air navigation services over Greenland above 19,500 feet and north of 63˚30"N in an area that is approximately 3,7 million square kilometers, roughly 70% of the Reykjavik Control Area.  Isavia ANS provides air navigation services over the upper airspace over Greenland on behalf of Iceland through a bilateral agreement with the Kingdom of Denmark that was signed in 1976.

Isavia ANS also provides approach and flight procedure design services in Greenland along with flight instrument testing as well as the installation and servicing of communication, surveillance and air navigation equipment.

Suluk APS, a subsidiary of Isavia ANS, provides approach and tower services at Kangerlussuaq airport.

Approach services for Reykjavik and Keflavik international airports are located in the Reykjavik area control center.  The approach area goes up to 24,500 feet and stretches out approximately 40 NM from Keflavik airport.

Traffic patterns within the Reykjavik Control Area consists of 5 main flow patterns.  Air traffic between Europe and North America consists of routes requested by airline operators and pilots with regard for jet stream currents which means that traffic density and routing can vary from day to day.

The traffic flow during the day consists mainly of flights traveling from Europe to North America and then the reverse during the night.