If you run out of stamina while flying, immediately stop flying.

Don't require stamina to stop flying.

defs.h

@@ -3893,7 +3893,7 @@ enum FLAG {
 	F_HOSTILE,	   // lf will attack the player if in sight
 	F_FRIENDLY,	   // lf will attack all non-players if in sight
 	F_FATALFOOD,	// if lf eats food with id = v0, they die.
-	F_NATURALFLIGHT,  // lf can fly natural using wings or similar
+	F_NATURALFLIGHT,  // lf can fly naturally using wings or similar
 	F_WANTS,	   // lf will try to pick up object type val0. 
 			   //	if val1 = B_COVETS, will even abandon attacks
 			   //	  for it!

lf.c

@@ -849,8 +849,13 @@ int cancast(lifeform_t *lf, enum OBTYPE oid, int *mpcost) {
 	// do we have enough stamina to do this?
 	stamcost = getstamcost(lf, oid);
 	if (stamcost && (getstamina(lf) < stamcost) && !lfhasflag(lf, F_NOSTAM)) {
-		reason = E_NOSTAM;
-		return B_FALSE;
+		// exception: you can always stop flying
+		if ((oid == OT_A_FLY) && isflyingwithwings(lf)) {
+			// ok
+		} else {
+			reason = E_NOSTAM;
+			return B_FALSE;
+		}
 	}
 
 	return castable;
@@ -14969,16 +14974,16 @@ flag_t *isfleeingfrom(lifeform_t *lf, lifeform_t *runfrom) {
 	return lfhasflagval(lf, F_FLEEFROM, runfrom->id, NA, NA, NULL);
 }
 
-int isflyingwithwings(lifeform_t *lf) {
+flag_t *isflyingwithwings(lifeform_t *lf) {
 	flag_t *retflag[MAXCANDIDATES];
         int nretflags,i;
 	getflags(lf->flags, retflag, &nretflags, F_FLYING, F_NONE);
 	for (i = 0; i < nretflags; i++) {
 		if (retflag[i]->lifetime == FROMABIL) {
-			return B_TRUE;
+			return retflag[i];
 		}
 	}
-	return B_FALSE;
+	return NULL;
 }
 
 int isfreebp(lifeform_t *lf, enum BODYPART bp, object_t *whatfor) {
@@ -19053,7 +19058,12 @@ void modstamina(lifeform_t *lf, float howmuch) {
 	}
 
 	if (getstamina(lf) == 0) {
+		flag_t *f;
 		stopsprinting(lf);
+		f = isflyingwithwings(lf);
+		if (f) {
+			killflag(f);
+		}
 	}
 }
 
@@ -26081,7 +26091,6 @@ int unweild(lifeform_t *lf, object_t *o) {
 int useability(lifeform_t *lf, enum OBTYPE aid, lifeform_t *who, cell_t *where) {
 	int rv;
 	flag_t *cwflag;
-	float stamcost = 0;
 	if (!cancast(lf, aid, NULL)) {
 		if (isplayer(lf)) {
 			// announce
@@ -26109,6 +26118,8 @@ int useability(lifeform_t *lf, enum OBTYPE aid, lifeform_t *who, cell_t *where)
 		return B_TRUE;
 	}
 
+	/*  Duplicate check.
+
 	stamcost = getstamcost(lf, aid);
 	if (stamcost) {
 		if (getstamina(lf) < stamcost) {
@@ -26118,6 +26129,7 @@ int useability(lifeform_t *lf, enum OBTYPE aid, lifeform_t *who, cell_t *where)
 			return B_TRUE;
 		}
 	}
+	*/
 
 	if (aid != OT_A_FULLSHIELD) {
 		killflagsofid(lf->flags, F_FULLSHIELD);

lf.h

@@ -379,7 +379,7 @@ int isdeaf(lifeform_t *lf);
 object_t *isdualweilding(lifeform_t *lf);
 flag_t *isfleeing(lifeform_t *lf);
 flag_t *isfleeingfrom(lifeform_t *lf, lifeform_t *runfrom);
-int isflyingwithwings(lifeform_t *lf);
+flag_t *isflyingwithwings(lifeform_t *lf);
 int isfreebp(lifeform_t *lf, enum BODYPART bp, object_t *whatfor);
 int isfriendly(lifeform_t *lf);
 int isfullyhealed(lifeform_t *lf);

spell.c

@@ -1370,18 +1370,14 @@ int abilityeffects(lifeform_t *user, enum OBTYPE abilid, cell_t *targcell, lifef
 		target->hp = 0;
 		killallobs(target->pack);
 	} else if (abilid == OT_A_FLY) {
-		flag_t *retflag[MAXCANDIDATES],*f;
-		int nretflags,i;
+		flag_t *f;
 
 		// already flying? stop.
-		getflags(user->flags, retflag, &nretflags, F_FLYING, F_NONE);
-		for (i = 0; i < nretflags; i++) {
-			f = retflag[i];
-			if (f->lifetime == FROMABIL) {
-				killflag(f);
-				taketime(user, getactspeed(user));
-				return B_FALSE;
-			}
+		f = isflyingwithwings(user);
+		if (f) {
+			killflag(f);
+			taketime(user, getactspeed(user));
+			return B_FALSE;
 		}
 
 		if (isimmobile(user)) {