Fix Chart.js loading issues with reliable CDN and add error handling

Author: patrickfreyer

flights/stats.html

@@ -88,7 +88,7 @@ <h3>Most Frequent Airlines</h3>
     const flightRoutesData = {{ site.data.flightRoutes | jsonify }};
 </script>
 
-<script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
+<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/4.4.0/chart.umd.js"></script>
 <script src="{{ '/js/flight-stats.js' | relative_url }}"></script>
 
 <style>

js/flight-stats.js

@@ -309,7 +309,30 @@ class FlightStatsCalculator {
 
 // Initialize when DOM is loaded
 document.addEventListener('DOMContentLoaded', function() {
+    console.log('DOM loaded, checking for data...');
+    
     if (typeof locationsData !== 'undefined' && typeof flightRoutesData !== 'undefined') {
-        new FlightStatsCalculator(locationsData, flightRoutesData);
+        console.log('Data found, initializing calculator...');
+        console.log('Locations:', locationsData.length);
+        console.log('Flights:', flightRoutesData.length);
+        
+        try {
+            new FlightStatsCalculator(locationsData, flightRoutesData);
+            console.log('FlightStatsCalculator initialized successfully');
+        } catch (error) {
+            console.error('Error initializing FlightStatsCalculator:', error);
+        }
+    } else {
+        console.error('Required data is missing:', {
+            locationsData: typeof locationsData,
+            flightRoutesData: typeof flightRoutesData
+        });
+    }
+    
+    // Check if Chart.js is loaded
+    if (typeof Chart === 'undefined') {
+        console.error('Chart.js is not loaded!');
+    } else {
+        console.log('Chart.js is loaded successfully');
     }
 });