Index: trunk/data/validator/deprecated.mapcss
===================================================================
--- trunk/data/validator/deprecated.mapcss	(revision 11439)
+++ trunk/data/validator/deprecated.mapcss	(revision 11476)
@@ -1119,4 +1119,10 @@
 }
 
+way[area][area!=yes][area!=no] {
+  throwError: tr("wrong value: {0}", "{0.tag}");
+  suggestAlternative: "area=yes";
+  suggestAlternative: "area=no";
+}
+
 /* #13953 */
 *[amenity=hunting_stand][lock=yes],
Index: trunk/data/validator/unnecessary.mapcss
===================================================================
--- trunk/data/validator/unnecessary.mapcss	(revision 11439)
+++ trunk/data/validator/unnecessary.mapcss	(revision 11476)
@@ -25,4 +25,12 @@
 }
 
+/* #14256 */
+area:closed[aeroway=aerodrome][area?],
+area:closed[aeroway=helipad][area?] {
+  throwWarning: tr("{0} is unnecessary for {1}", "{2.key}", "{1.tag}");
+  group: tr("unnecessary tag");
+  fixRemove: "{2.key}";
+}
+
 *[emergency=permissive] {
   /* see #9458 - emergency=permissive makes no sense */