Definition
A combined reference to two adjacent categories of controlled and advisory airspace. A control area (CTA) is a defined volume of controlled airspace extending upward from a specified altitude, within which air traffic control service is provided to IFR flights and, where applicable, to VFR flights. A flight information region (FIR) is a much larger block of airspace within which flight information service and alerting service are provided. Internationally, CTAs sit inside FIRs, so the paired abbreviation appears on charts and in NOTAMs when referring to either the controlled-area structure or the broader region surrounding it.
Plain English
Two kinds of airspace usually mentioned together. The control area is where controllers actively separate traffic. The flight information region is the larger surrounding zone where pilots get safety information and alerting help, but not full separation service.
Context Anchor
Seen most often in international flight planning, airspace information, and NOTAM-style notices that describe an affected area.
Derivation
‘Control area’ describes airspace where air traffic control service is provided. ‘Flight information region’ comes from ICAO terminology — a region where flight information (weather, traffic advisories, hazards) is offered to pilots. Pairing them reflects how ICAO airspace is layered: controlled areas nested inside a larger information region.
Why Pilots Care
Pilots must know CTA/FIR boundaries to comply with the correct communication and clearance requirements.
Intuition Check
Do not read “control area” as just any area controlled by an airport, and do not read “flight information region” as just a place where general flight information is stored. Here, both refer to defined blocks of airspace.
Example Sentence 1
The NOTAM applied to the entire Shanwick FIR, including the oceanic CTA above flight level 285.
Example Sentence 2
NOTAMs for the CTA/FIR were reviewed prior to departure to check for any temporary restrictions.