diff --git a/assets/static/js/app.js b/assets/static/js/app.js
index 246d905..8134dd2 100644
--- a/assets/static/js/app.js
+++ b/assets/static/js/app.js
@@ -927,7 +927,7 @@ class SkyView {
     update3DAircraftLabelContent(label, aircraft) {
         const callsign = aircraft.Callsign || aircraft.Icao || 'N/A';
         const altitude = aircraft.Altitude ? `${Math.round(aircraft.Altitude)}ft` : 'N/A';
-        const speed = aircraft.Speed ? `${Math.round(aircraft.Speed)}kts` : 'N/A';
+        const speed = aircraft.GroundSpeed ? `${Math.round(aircraft.GroundSpeed)}kts` : 'N/A';
         
         label.innerHTML = `
             <div style="font-weight: bold;">${callsign}</div>
@@ -1084,10 +1084,10 @@ class SkyView {
         
         // Convert position history to 3D world coordinates
         aircraft.position_history.forEach(pos => {
-            if (pos.latitude && pos.longitude) {
-                const x = (pos.longitude - originLon) * 111320 * Math.cos(pos.latitude * Math.PI / 180) / 1000;
-                const z = -(pos.latitude - originLat) * 111320 / 1000;
-                const y = (pos.altitude || 0) / 1000; // Convert feet to km
+            if (pos.lat && pos.lon) {
+                const x = (pos.lon - originLon) * 111320 * Math.cos(pos.lat * Math.PI / 180) / 1000;
+                const z = -(pos.lat - originLat) * 111320 / 1000;
+                const y = (pos.altitude || 0) / 1000; // Use historical altitude from position history
                 points.push(new THREE.Vector3(x, y, z));
             }
         });
@@ -1136,10 +1136,10 @@ class SkyView {
             
             // Convert position history to 3D world coordinates
             aircraft.position_history.forEach(pos => {
-                if (pos.latitude && pos.longitude) {
-                    const x = (pos.longitude - originLon) * 111320 * Math.cos(pos.latitude * Math.PI / 180) / 1000;
-                    const z = -(pos.latitude - originLat) * 111320 / 1000;
-                    const y = (pos.altitude || 0) / 1000; // Convert feet to km
+                if (pos.lat && pos.lon) {
+                    const x = (pos.lon - originLon) * 111320 * Math.cos(pos.lat * Math.PI / 180) / 1000;
+                    const z = -(pos.lat - originLat) * 111320 / 1000;
+                    const y = (pos.altitude || 0) / 1000; // Use historical altitude from position history
                     points.push(new THREE.Vector3(x, y, z));
                 }
             });
diff --git a/internal/merger/merger.go b/internal/merger/merger.go
index 0d907ce..f2dfb07 100644
--- a/internal/merger/merger.go
+++ b/internal/merger/merger.go
@@ -227,10 +227,11 @@ type SourceData struct {
 // PositionPoint represents a timestamped position update in aircraft history.
 // Used to build position trails for visualization and track analysis.
 type PositionPoint struct {
-	Time      time.Time `json:"time"`   // Timestamp when position was received
-	Latitude  float64   `json:"lat"`    // Latitude in decimal degrees
-	Longitude float64   `json:"lon"`    // Longitude in decimal degrees
-	Source    string    `json:"source"` // Source that provided this position
+	Time      time.Time `json:"time"`     // Timestamp when position was received
+	Latitude  float64   `json:"lat"`      // Latitude in decimal degrees
+	Longitude float64   `json:"lon"`      // Longitude in decimal degrees
+	Altitude  int       `json:"altitude"` // Altitude in feet (0 if unknown)
+	Source    string    `json:"source"`   // Source that provided this position
 }
 
 // SignalPoint represents a timestamped signal strength measurement.
@@ -655,6 +656,7 @@ func (m *Merger) updateHistories(state *AircraftState, aircraft *modes.Aircraft,
 				Time:      timestamp,
 				Latitude:  aircraft.Latitude,
 				Longitude: aircraft.Longitude,
+				Altitude:  aircraft.Altitude, // Include altitude in position history
 				Source:    sourceID,
 			})
 		}