Index: trunk/data/validator/combinations.mapcss
===================================================================
--- trunk/data/validator/combinations.mapcss	(revision 7922)
+++ trunk/data/validator/combinations.mapcss	(revision 7923)
@@ -106,4 +106,9 @@
 }
 
+/* {0.tag} without {1.key} */
+*[aeroway=terminal][!building] {
+  throwWarning: tr("{0} without {1}", "{0.tag}", "{1.key}");
+}
+
 /* {0.key} without {1.key} or {2.key} */
 *[incline                      ][!highway][!railway],