diff --git a/include/land.h b/include/land.h
index 85d0e3f2..b567dcad 100644
--- a/include/land.h
+++ b/include/land.h
@@ -194,6 +194,10 @@ struct llist {
     int supplied;
 };
 
+enum {
+    LND_AIROPS_EFF = 50		/* min. efficiency for air ops */
+};
+
 /* src/lib/subs/lndsub.c */
 extern void lnd_sweep(struct emp_qelem *, int, int, natid);
 extern int lnd_interdict(struct emp_qelem *, coord, coord, natid);
diff --git a/include/ship.h b/include/ship.h
index 0b715ca9..1b265e9c 100644
--- a/include/ship.h
+++ b/include/ship.h
@@ -214,6 +214,7 @@ struct mlist {
 #define CN_ERROR	(-1)
 
 enum {
+    SHP_AIROPS_EFF = 50,	/* min. efficiency for air ops */
     M_TORP_SHELLS = 3		/* number of shells used by a torpedo */
 };
 
diff --git a/src/lib/subs/mission.c b/src/lib/subs/mission.c
index 9e989803..114ef2b7 100644
--- a/src/lib/subs/mission.c
+++ b/src/lib/subs/mission.c
@@ -1115,8 +1115,8 @@ mission_pln_sel(struct emp_qelem *list, int wantflags, int nowantflags,
 	    if (ship.shp_effic < SHIP_MINEFF) {
 		goto shipsunk;
 	    }
-	    /* Can't fly off of ships < 50%, or non-owned or non-allied ships */
-	    if ((ship.shp_effic < 50) ||
+	    /* Can't fly off of inefficient or non-owned, non-allied ships */
+	    if ((ship.shp_effic < SHP_AIROPS_EFF) ||
 		((ship.shp_own != pp->pln_own) &&
 		 (getrel(getnatp(ship.shp_own), pp->pln_own) != ALLIED))) {
 		emp_remque(qp);
@@ -1138,8 +1138,8 @@ mission_pln_sel(struct emp_qelem *list, int wantflags, int nowantflags,
 	    if (land.lnd_effic < LAND_MINEFF)
 		goto landdead;
 
-	    /* Can't fly off of units < 50%, or non-owned or non-allied units */
-	    if ((land.lnd_effic < 50) ||
+	    /* Can't fly off of inefficient or non-owned, non-allied units */
+	    if ((land.lnd_effic < LND_AIROPS_EFF) ||
 		((land.lnd_own != pp->pln_own) &&
 		 (getrel(getnatp(land.lnd_own), pp->pln_own) != ALLIED))) {
 		emp_remque(qp);
diff --git a/src/lib/subs/plnsub.c b/src/lib/subs/plnsub.c
index ed7f9ea3..09c5af4d 100644
--- a/src/lib/subs/plnsub.c
+++ b/src/lib/subs/plnsub.c
@@ -466,7 +466,7 @@ pln_sel(struct nstr_item *ni, struct emp_qelem *list, struct sctstr *ap,
 		goto shipsunk;
 	    if (ship.shp_effic < SHIP_MINEFF)
 		goto shipsunk;
-	    if (ship.shp_effic < 50)
+	    if (ship.shp_effic < SHP_AIROPS_EFF)
 		continue;
 	    /* Can't fly off non-owned ships or non-allied ship */
 	    if ((ship.shp_own != player->cnum) &&
@@ -489,7 +489,7 @@ pln_sel(struct nstr_item *ni, struct emp_qelem *list, struct sctstr *ap,
 		goto landdead;
 	    if (land.lnd_effic < LAND_MINEFF)
 		goto landdead;
-	    if (land.lnd_effic < 50)
+	    if (land.lnd_effic < LND_AIROPS_EFF)
 		continue;
 	    /* Can't fly off units in ships or other units */
 	    if ((land.lnd_ship >= 0) || (land.lnd_land >= 0))