diff --git a/app/page.tsx b/app/page.tsx
index 40cccb6..9a5eb97 100644
--- a/app/page.tsx
+++ b/app/page.tsx
@@ -10,6 +10,7 @@ import AircraftForm from "../components/AircraftForm";
 import LegalDisclaimerModal from "../components/LegalDisclaimerModal";
 import LandingPage from "../components/LandingPage"; 
 import { isPointInPolygon, getCGLimitsAtWeight } from "../utils/calculations";
+import { validateFleetData } from "../utils/validation";
 
 export interface CustomStation {
   id: string;
@@ -48,7 +49,15 @@ export default function Home() {
   useEffect(() => {
     const loadedFleet = localStorage.getItem("wb_saved_fleet");
     if (loadedFleet) {
-      try { setSavedPlanes(JSON.parse(loadedFleet)); } catch (e) { console.error(e); }
+      try {
+        const parsed = JSON.parse(loadedFleet);
+        const validated = validateFleetData(parsed);
+        if (validated) {
+          setSavedPlanes(validated);
+        } else {
+          console.error("Loaded fleet data validation failed or was empty.");
+        }
+      } catch (e) { console.error(e); }
     }
     const savedTheme = localStorage.getItem("wb_theme");
     if (savedTheme === "dark") {
@@ -100,13 +109,15 @@ export default function Home() {
     reader.onload = (event) => {
       try {
         const json = JSON.parse(event.target?.result as string);
-        if (Array.isArray(json)) {
-          setSavedPlanes(json);
-          localStorage.setItem("wb_saved_fleet", JSON.stringify(json));
+        const validated = validateFleetData(json);
+
+        if (validated) {
+          setSavedPlanes(validated);
+          localStorage.setItem("wb_saved_fleet", JSON.stringify(validated));
           alert("Fleet imported successfully!");
           setShowSettings(false);
         } else {
-          alert("Invalid file format.");
+          alert("Invalid file format or corrupted data.");
         }
       } catch (err) {
         alert("Error parsing file.");
diff --git a/package-lock.json b/package-lock.json
index 5095447..7dec538 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -26,7 +26,7 @@
         "@types/react-dom": "^19",
         "autoprefixer": "^10.4.19",
         "cross-env": "^10.1.0",
-        "eslint": "^9",
+        "eslint": "^9.39.2",
         "eslint-config-next": "16.0.10",
         "postcss": "^8.4.31",
         "tailwindcss": "^3.4.17",
diff --git a/package.json b/package.json
index 4d242ac..3760ab8 100644
--- a/package.json
+++ b/package.json
@@ -28,7 +28,7 @@
     "@types/react-dom": "^19",
     "autoprefixer": "^10.4.19",
     "cross-env": "^10.1.0",
-    "eslint": "^9",
+    "eslint": "^9.39.2",
     "eslint-config-next": "16.0.10",
     "postcss": "^8.4.31",
     "tailwindcss": "^3.4.17",
diff --git a/public/sw.js b/public/sw.js
index d7b0292..1578bf5 100644
--- a/public/sw.js
+++ b/public/sw.js
@@ -1 +1 @@
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+if(!self.define){let e,s={};const a=(a,n)=>(a=new URL(a+".js",n).href,s[a]||new Promise(s=>{if("document"in self){const e=document.createElement("script");e.src=a,e.onload=s,document.head.appendChild(e)}else e=a,importScripts(a),s()}).then(()=>{let e=s[a];if(!e)throw new Error(`Module ${a} didn’t register its module`);return e}));self.define=(n,i)=>{const t=e||("document"in self?document.currentScript.src:"")||location.href;if(s[t])return;let c={};const r=e=>a(e,t),d={module:{uri:t},exports:c,require:r};s[t]=Promise.all(n.map(e=>d[e]||r(e))).then(e=>(i(...e),c))}}define(["./workbox-f1770938"],function(e){"use 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diff --git a/utils/validation.ts b/utils/validation.ts
new file mode 100644
index 0000000..814204f
--- /dev/null
+++ b/utils/validation.ts
@@ -0,0 +1,65 @@
+import { Aircraft, SavedAircraft } from "../data/aircraft";
+
+/**
+ * Validates if the input is a valid SavedAircraft object.
+ */
+function isValidSavedAircraft(obj: any): obj is SavedAircraft {
+  if (typeof obj !== 'object' || obj === null) return false;
+
+  // Check required string fields
+  if (typeof obj.id !== 'string') return false;
+  if (typeof obj.model !== 'string') return false;
+  // registration is optional in base Aircraft but usually present in SavedAircraft
+  if (obj.registration !== undefined && typeof obj.registration !== 'string') return false;
+
+  // Check required number fields
+  if (typeof obj.emptyWeight !== 'number' || !Number.isFinite(obj.emptyWeight)) return false;
+  if (typeof obj.emptyArm !== 'number' || !Number.isFinite(obj.emptyArm)) return false;
+
+  // Check stations array
+  if (!Array.isArray(obj.stations)) return false;
+  for (const station of obj.stations) {
+    if (typeof station !== 'object' || station === null) return false;
+    if (typeof station.id !== 'string') return false;
+    if (typeof station.name !== 'string') return false;
+    if (typeof station.arm !== 'number' || !Number.isFinite(station.arm)) return false;
+  }
+
+  // Check envelope array
+  if (!Array.isArray(obj.envelope)) return false;
+  for (const point of obj.envelope) {
+    if (typeof point !== 'object' || point === null) return false;
+    if (typeof point.cg !== 'number' || !Number.isFinite(point.cg)) return false;
+    if (typeof point.weight !== 'number' || !Number.isFinite(point.weight)) return false;
+  }
+
+  // Check optional fields if present
+  if (obj.isCustomPlane !== undefined && typeof obj.isCustomPlane !== 'boolean') return false;
+
+  if (obj.savedArmOverrides !== undefined) {
+    if (typeof obj.savedArmOverrides !== 'object' || obj.savedArmOverrides === null) return false;
+    for (const key in obj.savedArmOverrides) {
+        if (typeof obj.savedArmOverrides[key] !== 'number' || !Number.isFinite(obj.savedArmOverrides[key])) return false;
+    }
+  }
+
+  return true;
+}
+
+/**
+ * Validates if the input is an array of SavedAircraft objects.
+ * Use this when loading fleet data from LocalStorage or file import.
+ */
+export function validateFleetData(data: any): SavedAircraft[] | null {
+  if (!Array.isArray(data)) return null;
+
+  // Filter out any invalid aircraft objects to ensure robustness
+  // Or return null if strictly enforcing integrity.
+  // Defense in depth: Let's clean the data by filtering valid items only.
+  const validFleet = data.filter(isValidSavedAircraft);
+
+  // If the array was not empty but no valid items found, it might be the wrong format completely.
+  if (data.length > 0 && validFleet.length === 0) return null;
+
+  return validFleet;
+}