diff --git a/src/main/lemondronor/advisorycircular.cljs b/src/main/lemondronor/advisorycircular.cljs
index d0ccb95..794471f 100644
--- a/src/main/lemondronor/advisorycircular.cljs
+++ b/src/main/lemondronor/advisorycircular.cljs
@@ -324,7 +324,7 @@
          ;; Landmark.
          "?:[{nearbydistance} miles from {nearbylandmark} ]"
          ;; Hashtag based on registration.
-         "?:[#{registration} |#{militaryregistration} ]"
+         "?:[#{registration|hashtag} |#{militaryregistration|hashtag} ]"
          ;; tar1090 link.
          "https://tar1090.adsbexchange.com/?icao={icao}&zoom=13")]))
 
diff --git a/src/main/lemondronor/advisorycircular/generation.cljc b/src/main/lemondronor/advisorycircular/generation.cljc
index a0cc0c9..f7adbda 100644
--- a/src/main/lemondronor/advisorycircular/generation.cljc
+++ b/src/main/lemondronor/advisorycircular/generation.cljc
@@ -63,7 +63,8 @@
              (if (re-find #"^[FHLMNRSX](\b|[A-Z0-9])" s)
                (str "an " s)
                (str "a " s))
-             (str "an " s)))})
+             (str "an " s)))
+   :hashtag #(string-replace % #"-" "_")})
 
 
 (defn apply-filter [s filter-name]