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WHAT FIT TO FLY, IN-FLIGHT AND CREW SUPPORT PATTERNS CAN TELL AIRLINES AHEAD OF SEASONAL PEAKS
Every December, MedAire’s case volumes climb. Last year was no exception: daily volumes peaked in late December and remained elevated into January 2026 across Fit to Fly, In-Flight and Crew Support.
Justin Devlin, Medical Director for Aviation Services
MedAire
"Before drawing conclusions, it helps to put the figures in context. We handle more cases over the holidays, but as MedAire don't hold commercial aviation volume figures, we can't say whether illness or injury becomes more likely. Increase is likely to reflect more people flying and that distinction is the lens for everything below."
Data used: MedAire case records, 1 January to 31 December 2025, plus January 2026 for comparison across our core services: fit-to-fly, in-flight and crew support.
Section 01
What the Data TellS Us About Risk
Across all three services, the rate of serious outcomes stayed flat year-round. The Fit to Fly denial rate held at roughly 17 to 18% in both quiet and peak months. The percentage of In-Flight cases ending in a medical diversion remained in line with MedAire's 2025 full-year diversion rate of 1.68%. December produced the highest number of diversions and hospital transports of any month in raw terms, simply because it produced the most cases overall.
The key takeaway: case volumes rose, while the proportion of severe cases stayed steady.
+15%
Fit to Fly peak vs. avg
+31%
In-Flight peak vs. avg
+15–20%
Crew Support vs. mid-year
Section 02
Fit to Fly: The Quiet-But-Real Peak
December was the busiest month of the year for Fit to Fly. Here is what the data showed:
December was the busiest month of the year, running about 15% above the rest-of-year average, roughly 252 cases a day against a typical 218.
Our busiest single day of the entire dataset was 5 January 2026, with 320 cases. The surge didn't end when the calendar turned.
Vomiting cases accounted for 15% of January cases, against 13% in a typical month, potentially reflecting changes in eating habits and social activity over the holidays.
The "advised against travel" rate stayed consistent across the year at roughly 17 to 18%. December simply produced the highest number of those calls in absolute terms (1,339).
For more on how these decisions are made, listen to our Fit to Fly podcast episode.
Section 03
In-Flight: The Clearest Volume Spike of the Three
In-Flight saw the sharpest seasonal climb of all three services. The data tells a consistent story:
December ran about 31% above a typical month: 232 cases a day against roughly 176.
The climb built steadily from October through November before peaking in the final ten days of December.
Neurological events, MedAire's single largest in-flight category at 38%, stayed the leading cause of calls throughout the peak, consistent with the rest of the year.
Gastrointestinal cases (nausea, vomiting and abdominal pain) are MedAire's second most common in-flight category overall at 23% of cases, and the winter months saw this climb further: vomiting cases hit 777 in December and 794 in January, against 470 to 615 in other months.
December produced the year's highest number of medical diversions (101) and hospital transports (568) in absolute terms, while the underlying diversion rate held flat.
Doha's case volume climbed steadily through the year, from around 410 cases a month in spring to 608 in December, the clearest single-hub trend in the data.
Section 04
Crew Support: Seasonal Shifts in the Case Mix
Despite higher Crew Support volumes in December and January, the overall mix of cases remained relatively consistent. Looking more closely, however, some categories show movement through the winter period.
Crew Support ran about 15 to 20% above its mid-year baseline in both December and January.
Respiratory cases increased progressively through the winter period, from 13.1% of cases in November to 14.6% in December and 15.6% in January.
ENT cases (tonsillitis, blocked ears etc) remained elevated, while gastrointestinal illness continued to account for the largest share of Crew Support cases, at close to three in ten.
Most cases resolved with outpatient care or monitoring. Only about 3% required inpatient treatment.
Section 05
Turning Your Airline's Data Into Action
MedAire offers both on-demand client reporting and business reviews to help airlines compare their own case data with industry trends and identify passenger and crew patterns across their fleets.
The January peak in respiratory illness for crewmembers, a category that includes seasonal illnesses such as flu, is a good example of how these insights can be put into practice. For airlines seeing a similar pattern in their own Crew Support data, the period ahead of the holiday season could be an opportunity to reinforce flu season guidance to crewmembers.
But seasonal priorities will differ between airlines. Route networks and operating environments can introduce different considerations. An operator flying frequently to cold-weather destinations, for example, may also want to promote practical precautions around slips, falls and other winter-related risks.
As the next holiday peak approaches
Three practical steps can help turn the data into action:
1
Review your own case history to see whether it reflects patterns such as the January rise in gastrointestinal illness.
2
Time crew health messaging to what the mix of cases shows.
3
Use the MedAire Portal to understand the impact of global medical risks to support health initiatives.
40+ Years of Aviation Experience
Keeping Crews in Safe Hands, Whatever the Season
40+ years of aviation experience and case data give MedAire unique insight into how demand changes across seasons, helping us anticipate pressure points and scale our assistance accordingly. This insight is backed by medical and security expertise, intelligence, training, equipment and global network capabilities, helping airlines prepare for and manage the demands of every season.