A Functional Airspace Block (FAB) is as an airspace block based on operational requirements and established regardless of State boundaries. 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.
Nine FAB initiatives have been taken; two of these have already been implemented, namely the UK-Ireland and Denmark-Sweden FABs:
- NEFAB (North European FAB): Estonia, Finland, Latvia, Norway.
- Denmark-Sweden: Denmark, Sweden
- 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 Bulgaria, Romania
- BLUE MED Italy, Malta, Greece, Cyprus, (and Egypt, Tunisia, Albania, Jordan as observers)
- UK- IRELAND FAB United Kingdom, Ireland
- SW FAB (South West FAB) Portugal, Spain