Environment - Slovakia
PRB monitoring
Slovakia registered a KEA performance of 4.27%. Their target of 4.01% was not achieved and Slovakia did not contribute positively to Union-wide performance. The NSA states the main reason for not meeting the target is that performance was affected by the continued closure of Ukrainian airspace, which required traffic rerouting and resulted in longer trajectories.
Both KEP and KES deteriorated in comparison with 2024.
VFE of the actual en route trajectory was at 77.57%, which was better than the average Union-wide performance.
No airports are included in the performance plan for monitoring.
En route performance
Horizontal flight efficiency of the actual trajectory (KEA) (KPI#1), of the last filed flight plan (KEP) (PI#1), shortest constrained route (KES) (PI#2) and vertical flight efficiency of the actual trajectory (VFE) (PI#3)
NoteFocus on en route performance
KEA
The value for KEA has been deteriorating in 2025 with respect to 2024 (4.27% vs 4.05%), while the value of KEA corrected for the influence of the war in Ukraine has been stable (2.12% in 2024 and 2025). In 2025, Slovakia is 23rd for KEA and 16th for KEA corrected.
Slovakia is second best in terms of average additional km per flight with respect to the direct (0.35 km), but 11th in terms of overall additional distance (5.48 km per flight).
In terms of overall additional distance Slovakia is 9th, with 1.22%.
Regarding the assessment of the achieved level of actual performance in the environment KPA, the NSA reports: “Flight efficiency has declined due to multiple factors. The gap between flight plan and actual flown trajectories remains an issue. While tactical shortcuts can reduce fuel burn, they increase network variability. Reviewing and reducing ATM related network constraints as early as possible to allow flight plans that better align with actual trajectories would improve both efficiency and predictability for all stakeholders.
A number of events in 2025 affected the network and had direct consequences on the flight efficiency evolution:
The closure and avoidance of Ukrainian, Belarusian and Russian airspace forced traffic to reroute through neighbouring countries (Türkiye, Bulgaria, Romania, Poland, Slovakia, Hungary, Lithuania, Latvia and Estonia, etc.). This shifted significant demand to adjacent ACCs/UACs, especially Far Eastern traffic, and led to increased route extensions.
KEA, KEP, KES and other indicators are valuable – but they do not describe the full runway-to-runway fuel optimum.”
Regarding the implementation of major operational or structural changes during the calendar year impacting performance in this key performance area, the NSA reports: “Two Free Route Airspace (FRA) projects were successfully implemented on 28 November 2024:
1) FRA interface between SECSI FRA and SEE FRA (Vienna, Praha, Bratislava, Budapest CTAs) and
2) FRA interface between Baltic FRA and SEE FRA (Praha CTA). In both projects, FRA is available 24/7 and flight planning does not require intermediate points along the FRA boundaries. The new interfaces reduce complexity and improve horizontal flight efficiency.
from Q4/2026 to Q1/2027 - LBSR/LRBB/LZBB/LUUU/EPWW/EYVC/UKOV - cross-border FRA Operations between SEE FRA, FRA Poland (Baltic FRA) and FRA Ukraine.”
Regarding progress on the implementation of the measures committed to in the ERNIP, the NSA reports: “Environment KPA related initiatives will address the Strategic Priority implementation related to seamless airspace organisation through the implementation of the
ENV(1) Airspace changes included in the ERNIP Part 2 - ARN version 2021-2030, including major areas of cross border Free Route Airspace (FRA) - 0.05 pp of the KEP improvement for the entire RP4, i.e. 0.01 pp average reduction every year.
ENV(2) NM Flight Efficiency strategic project - 0.10 pp of the KEP improvement for the entire RP4, i.e. 0.02 pp average reduction every year.
ENV(3) ASM and Advanced FUA Network Strategic Programme and the RAD measures re-organisation and rationalisation - 0.42 pp of the KEP improvement for the entire RP4, i.e. 0.08-0.09 pp average reduction every year.
ENV(4) Stepped implementation of the various Concepts of Operations covering - Integrated Data Layer (iDL), Network 4D Trajectory, ASM/ATFCM Integration and FLOW.”
Regarding the identification and analysis by the NSA of the underlying reasons or circumstances having led to the performance target not being achieved, the NSA reports: “The NSA acknowledges that the achieved KEA value for 2025 exceeded the target value established in the Performance Plan. Based on the information provided by the ANSP and the analysis performed by the NSA, the main contributing factors were predominantly external to the ANSP's direct control. These include the continued closure and avoidance of Ukrainian, Belarusian and Russian airspace, resulting in significant rerouting of traffic flows through neighbouring States and increased route extensions across the European ATM network.”
Regarding recommendations to the ANSP to rectify the situation, the NSA reports: “The NSA recommends that the ANSP continue to actively support and accelerate initiatives aimed at improving horizontal flight efficiency, including the further development and expansion of cross-border Free Route Airspace operations and enhanced cooperation with neighbouring ANSPs and the Network Manager.
The ANSP should continue monitoring ATM-related constraints affecting flight efficiency and identify opportunities to reduce route deviations where operationally feasible. Particular attention should be paid to the optimisation of airspace design, implementation of ERNIP environmental initiatives and participation in network-wide programmes addressing flight efficiency and trajectory management.
The NSA further recommends maintaining regular assessment of the effectiveness of implemented measures and reporting on their contribution to the achievement of future environmental performance targets.”
Regarding remedial measures that have been / will be taken by the ANSP to rectify the situation, the NSA reports: “The NSA has reviewed the remedial measures proposed by the ANSP and considers them appropriate in view of the identified causes of the performance shortfall. The ANSP will continue the implementation of environmental initiatives contained in the ERNIP, including further development of cross-border Free Route Airspace operations, participation in the NM Flight Efficiency Programme, optimisation of ASM/FUA processes and implementation of network trajectory management concepts.
The planned implementation of cross-border FRA operations between SEE FRA, Baltic FRA and FRA Ukraine, together with the continued deployment of strategic network initiatives, is expected to contribute positively to future flight efficiency performance. The NSA will continue monitoring the implementation and effectiveness of these measures through its regular performance oversight activities and annual performance review process.”
Regarding the follow up of the remedial measures indicated in the previous monitoring report(s), the NSA reports: “The conflict in Ukraine still affects overflights.
Closure of Ukrainian airspace and to establishment of military transit corridors has caused a significant shift of traffic flows to the west with the extraordinate de-tour impacting of KEA indicator.”
KEP
Regarding initiatives implemented or planned that will improve this PI and how does the NSA intend on monitoring their effectiveness on performance, the NSA reports: “Two Free Route Airspace (FRA) projects were successfully implemented on 28 November 2024: 1) FRA interface between SECSI FRA and SEE FRA (Vienna, Praha, Bratislava, Budapest CTAs) and 2) FRA interface between Baltic FRA and SEE FRA (Praha CTA). In both projects, FRA is available 24/7 and flight planning does not require intermediate points along the FRA boundaries. The new interfaces reduce complexity and improve horizontal flight efficiency.
from Q4/2026 to Q1/2027 - LBSR/LRBB/LZBB/LUUU/EPWW/EYVC/UKOV - cross-border FRA Operations between SEE FRA, FRA Poland (Baltic FRA and FRA Ukraine.
Due to the impact of the war in Ukraine, it is not possible to directly compare the KEP RP3 and RP4 targets.
A number of events in 2025 affected the network and had direct consequences on the flight efficiency evolution:
The closure and avoidance of Ukrainian, Belarusian and Russian airspace forced traffic to reroute through neighbouring countries (Türkiye, Bulgaria, Romania, Poland, Slovakia, Hungary, Lithuania, Latvia and Estonia, etc.). This shifted significant demand to adjacent ACCs/UACs, especially Far Eastern traffic, and led to increased route extensions.
KEA, KEP, KES and other indicators are valuable – but they do not describe the full runway-to-runway fuel optimum.”
KES
Regarding initiatives implemented or planned that will improve this PI and how does the NSA intend on monitoring their effectiveness on performance, the NSA reports: “Two Free Route Airspace (FRA) projects were successfully implemented on 28 November 2024: 1) FRA interface between SECSI FRA and SEE FRA (Vienna, Praha, Bratislava, Budapest CTAs) and 2) FRA interface between Baltic FRA and SEE FRA (Praha CTA). In both projects, FRA is available 24/7 and flight planning does not require intermediate points along the FRA boundaries. The new interfaces reduce complexity and improve horizontal flight efficiency.
from Q4/2026 to Q1/2027 - LBSR/LRBB/LZBB/LUUU/EPWW/EYVC/UKOV - cross-border FRA Operations between SEE FRA, FRA Poland (Baltic FRA and FRA Ukraine).
The KES indicator does not directly capture actual environmental performance, as the trajectory flown can differ significantly due to factors beyond ANSP control. KEA, KEP, KES and other indicators are valuable – but they do not describe the full runway-to-runway fuel optimum.
A number of events in 2025 affected the network and had direct consequences on the flight efficiency evolution:
The closure and avoidance of Ukrainian, Belarusian and Russian airspace forced traffic to reroute through neighbouring countries (Türkiye, Bulgaria, Romania, Poland, Slovakia, Hungary, Lithuania, Latvia and Estonia, etc.). This shifted significant demand to adjacent ACCs/UACs, especially Far Eastern traffic, and led to increased route extensions.”
Vertical flight efficiency
Regarding initiatives implemented or planned that will improve this PI and how does the NSA intend on monitoring their effectiveness on performance, the NSA reports: “Total distance (km) 66,802,844
Distance flown at altitude ≥ Requested FL - 1000 ft - 51,821,671
Indicator (%) 77.6
Based on data available as of early 2026, the vertical flight efficiency of the actual trajectory (VFE) for Slovakia in 2025 has been influenced by a significant increase in traffic and airspace restrictions in Central Europe, leading to continued environmental performance challenges.
A number of events in 2025 affected the network and had direct consequences on the flight efficiency evolution:
The closure and avoidance of Ukrainian, Belarusian and Russian airspace forced traffic to reroute through neighbouring countries (Türkiye, Bulgaria, Romania, Poland, Slovakia, Hungary, Lithuania, Latvia and Estonia, etc.). This shifted significant demand to adjacent ACCs/UACs, especially Far Eastern traffic, and led to increased route extensions.”
NoteFocus on Civil-Military dimension
Effective use of reserved or segregated local airspace
SLOVAKIA reports a ratio of 84% - Total number of hours allocated & notified to NM: 38,874 - Total number of hours used: 32,830 BRATISLAVA ACC reports a ratio of 80% - Total number of hours allocated & notified to NM: 21,240 - Total number of hours used: 16,913
Regarding initiatives implemented or planned that will improve this PI and how does the NSA intend on monitoring their effectiveness on performance, the NSA reports: “PRISMIL CURA was fully implemented”
Rate of planning via available airspace structures
SLOVAKIA reports that: - The ratio of planning via available airspace structures is 99% (via available restricted and segregated airspaces)
Regarding initiatives implemented or planned that will improve this PI and how does the NSA intend on monitoring their effectiveness on performance, the NSA reports: “PRISMIL CURA was fully implemented”
Rate of using available airspace structures
SLOVAKIA reports that: - The ratio of the use of the available airspace structures is 86% (via available restricted and segregated airspaces)
Regarding initiatives implemented or planned that will improve this PI and how does the NSA intend on monitoring their effectiveness on performance, the NSA reports: “PRISMIL CURA was fully implemented”