Add US airspace levels, for some reason

macrovision.js

@@ -944,6 +944,14 @@ function drawVerticalScale(ifDirty = false) {
         drawAltitudeLine(ctx, math.unit(0.1, "um"), "Gold Leaf");
         drawAltitudeLine(ctx, math.unit(35, "um"), "PCB Trace");
     }
+        
+    if (config.drawAltitudes == "airspaces" || config.drawAltitudes == "all") {
+        drawAltitudeLine(ctx, math.unit(18000, "feet"), "Class A");
+        drawAltitudeLine(ctx, math.unit(14500, "feet"), "Class E");
+        drawAltitudeLine(ctx, math.unit(10000, "feet"), "Class B");
+        drawAltitudeLine(ctx, math.unit(4000, "feet"), "Class C");
+        drawAltitudeLine(ctx, math.unit(2500, "feet"), "Class D");
+    }
 }
 
 // this is a lot of copypizza...
@@ -2336,7 +2344,8 @@ const settingsData = {
             "weather",
             "water",
             "geology",
-            "thicknesses"
+            "thicknesses",
+            "airspaces",
         ],
         get value() {
             return config.drawAltitudes;