# UNDF: UNDF-2026-000000979
--- a/src/Airports/groundnetwork.hxx
+++ b/src/Airports/groundnetwork.hxx
@@ -8,6 +8,7 @@

 #include <string>
 #include <unordered_map>
+#include <unordered_set>

 #include <simgear/compiler.h>

@@ -189,6 +190,7 @@

     FGParkingList m_parkings;
     FGTaxiNodeVector m_nodes;
+    std::unordered_set<FGTaxiNode*> m_nodeSet;  // O(1) dedup for addSegment/addParking

     FGTaxiNodeRef findNodeByIndex(int index) const;

--- a/src/Airports/groundnetwork.cxx
+++ b/src/Airports/groundnetwork.cxx
@@ -558,22 +558,22 @@
 void FGGroundNetwork::addSegment(const FGTaxiNodeRef& from, const FGTaxiNodeRef& to)
 {
     FGTaxiSegment* seg = new FGTaxiSegment(from, to);
     segments.push_back(seg);

-    FGTaxiNodeVector::iterator it = std::find(m_nodes.begin(), m_nodes.end(), from);
-    if (it == m_nodes.end()) {
+    if (m_nodeSet.find(from.get()) == m_nodeSet.end()) {
+        m_nodeSet.insert(from.get());
         m_nodes.push_back(from);
     }

-    it = std::find(m_nodes.begin(), m_nodes.end(), to);
-    if (it == m_nodes.end()) {
+    if (m_nodeSet.find(to.get()) == m_nodeSet.end()) {
+        m_nodeSet.insert(to.get());
         m_nodes.push_back(to);
     }
 }

 void FGGroundNetwork::addParking(const FGParkingRef& park)
 {
     m_parkings.push_back(park);

-    FGTaxiNodeVector::iterator it = std::find(m_nodes.begin(), m_nodes.end(), park);
-    if (it == m_nodes.end()) {
+    if (m_nodeSet.find(park.get()) == m_nodeSet.end()) {
+        m_nodeSet.insert(park.get());
         m_nodes.push_back(park);
     }
 }