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Amid a record-breaking summer for European aviation, the SITA ATN network delivered uninterrupted service — demonstrating its resilience, scalability, and vital role in supporting the industry's continued growth.
In Summer 2025, air traffic soared to new post-pandemic highs, peaking at 37,000 flights per day. Many airlines expanded routes, increased flight frequencies, and operated at full capacity to meet strong passenger demand. Behind the scenes — beyond the full airports and busy skies — a quiet, powerful force worked around the clock to keep things moving smoothly: the SITA ATN network
Setting New Standards in Network Reliability
As demand surged across Europe’s airspace, the SITA ATN network delivered outstanding performance — with zero service outages and record-low latency levels throughout the summer. The network has maintained full availability since the start of 2025, a testament to its resilience and reliability amid the high volume of operational messages transmitted daily by airlines, air navigation service providers (ANSPs), and controllers across the region.
This level of performance is the result of months of preparation, sustained technical investment, and close collaboration between SITA, EUROCONTROL NM, ANSPs, and other aviation stakeholders — reflecting what’s possible when the community works together towards shared goals.
What Success Looked Like:
- Zero outages across the SITA ATN network across the year and including during summer period, from May to September.
- CPDLC usage reached record levels, with over 60% of aircraft in European airspace connected on peak days — driving more efficient, data-driven operations.
This unprecedented adoption reflects the growing trust that controllers and pilots are placing in datalink — and the benefits are now being seen in improved airspace capacity and operational efficiency. - An 18% year-over-year increase in CPDLC traffic highlights broader adoption and growing operational maturity — with the number of transactions also rising on a per-flight basis.
- ATFCM (Air Traffic Flow and Capacity Management) delay impact reduced dramatically – from over 500 hours in 2024 to virtually zero in 2025- underscoring the role of stable datalink services in improving traffic flow.
Strategic Investments Behind Performance
This performance was underpinned by a series of strategic investments by SITA designed to increase resilience, reduce risk and prepare the network for future growth:
- Dual-path data center connectivity was introduced to provide full network redundancy, with 83% of European traffic supported from two different locations by the end of June — significantly enhancing overall resilience of the European network.
- A third alternate frequency was deployed across large parts of Europe, with further rollout planned. This upgrade significantly improves transaction latency and predictability. Adding one more frequency increases VDL capacity by 50%, expanding from two to three alternates.
- New policies now govern the use of test systems in the live environment, enabling critical research initiatives like SESAR to continue without compromising production stability.
- Shifting from post‑operational analysis to proactive monitoring now enables earlier detection and timely mitigation of disruptions — ensuring continuity of operations.
VDLm2: Proven, Trusted and Ready to Sustain Growth
One of the key takeaways from Summer 2025 is the continued relevance of VDLm2 (VHF Data Link Mode 2) in supporting European airspace communications.
Today CPDLC supports around 60% of all commercial flights in Europe- meaning that on peak days, more than 22,000 flights relied on the VDLm2 network. This is a clear testament to its criticality, scalability and ability to support continued traffic growth.
Looking Ahead
Summer 2025 wasn’t just a period of high traffic — it was a benchmark moment in the evolution of datalink communications in European aviation. It shows what’s possible when the industry comes together with a shared mission: keeping aviation safe, connected, and efficient.
At SITA we’re proud of what’s been achieved — and even more excited about what lies ahead. The journey doesn’t stop here. As traffic continues to grow and operational demands increase, we remain committed to:
- Ongoing investment in the VDLm2 network
- Driving innovation through industry collaboration
- Leading advancements in datalink communications by applying CPDLC best practices, optimizing transactions, and developing improved reporting tools, as the community prepares for Baseline 2 operations and explores solutions for the HyperConnected aircraft.
A Collective Effort
A sincere thank you to all our partners — EUROCONTROL NM, ANSPs, airlines, and technology collaborators — whose shared efforts made this summer not just possible, but truly exceptional. Together, we've demonstrated what a connected aviation community can achieve — setting a new standard for performance and reliability in Europe's skies.
Here's to what we've accomplished — and to everything we'll continue building, together.
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