The FAB concept was developed in the 1st legislative package of the Single European Sky (SES I) as one of the main means for reducing airspace fragmentation. The 2nd legislative package (SES II) tackled the creation of FABs in terms of service provision, in addition to the airspace organisation issues.
The twofold objective of the legislative packagers is to optimise air traffic flows and increase the efficiency of air traffic services in Europe.
SES II lays down a definite commitment date for the Member States to improve performance by implementing FABs, i.e. 4 December 2012. Nine FAB initiatives have been taken:
| Short name | Name | Countries |
|---|---|---|
| NEFAB | North European FAB | Estonia, Finland, Latvia, Norway |
| Denmark-Sweden | Denmark-Sweden | Denmark, Sweden |
| BALTIC FAB | BALTIC FAB | Poland, Lithuania |
| FABEC | FAB Europe Central | France, Germany, Belgium, Netherlands, Luxembourg, and Switzerland |
| FABCE | FAB Central Europe | Czech Republic, Slovak Republic, Austria, Hungary, Croatia, Slovenia, Bosnia and Herzegovina |
| DANUBE | DANUBE | Bulgaria, Romania |
| BLUE MED | BLUE MED | Italy, Malta, Greece, Cyprus, (and Egypt, Tunisia, Albania, Jordan as observers) |
| UK-IRELAND FAB | UK-IRELAND FAB | United Kingdom, Ireland |
| SW FAB | South West FAB | Portugal, Spain |
For the details about the computation of delay at FAB level (i.e. the FIRs used), please refer to the relevant section in the En-route ATFM delays page part of the Datasets Definition section.