diff --git a/api.lua b/api.lua
index 530a852..d219850 100644
--- a/api.lua
+++ b/api.lua
@@ -8,7 +8,7 @@ local use_cmi = minetest.global_exists("cmi")
 
 mobs = {
 	mod = "redo",
-	version = "20201205",
+	version = "20201206",
 	intllib = S,
 	invis = minetest.global_exists("invisibility") and invisibility or {}
 }
@@ -112,6 +112,7 @@ local mob_class = {
 	light_damage_max = 15,
 	water_damage = 0,
 	lava_damage = 0,
+	air_damage = 0,
 	suffocation = 2,
 	fall_damage = 1,
 	fall_speed = -10, -- must be lower than -2 (default: -10)
@@ -1100,6 +1101,19 @@ function mob_class:do_env_damage()
 		end
 	end
 
+	-- air damage
+	if self.air_damage ~= 0 and self.standing_in == "air" then
+
+		self.health = self.health - self.air_damage
+
+		effect(pos, 3, "bubble.png", 1, 1, 1, 0.2)
+
+		if self:check_for_death({type = "environment",
+				pos = pos, node = self.standing_in}) then
+			return true
+		end
+	end
+
 	-- is mob light sensative, or scared of the dark :P
 	if self.light_damage ~= 0 then
 
@@ -2084,6 +2098,15 @@ function mob_class:follow_flop()
 		if not self:attempt_flight_correction() then
 
 			self.state = "flop"
+
+			-- do we have a custom on_flop function?
+			if self.on_flop then
+
+				if self:on_flop(self) then
+					return
+				end
+			end
+
 			self.object:set_velocity({x = 0, y = -5, z = 0})
 
 			self:set_animation("stand")
@@ -3482,6 +3505,7 @@ minetest.register_entity(name, setmetatable({
 	owner = def.owner,
 	order = def.order,
 	on_die = def.on_die,
+	on_flop = def.on_flop,
 	do_custom = def.do_custom,
 	jump_height = def.jump_height,
 	drawtype = def.drawtype, -- DEPRECATED, use rotate instead
@@ -3505,6 +3529,7 @@ minetest.register_entity(name, setmetatable({
 	light_damage_max = def.light_damage_max,
 	water_damage = def.water_damage,
 	lava_damage = def.lava_damage,
+	air_damage = def.air_damage,
 	suffocation = def.suffocation,
 	fall_damage = def.fall_damage,
 	fall_speed = def.fall_speed,
diff --git a/api.txt b/api.txt
index e8014ed..7001891 100644
--- a/api.txt
+++ b/api.txt
@@ -64,6 +64,7 @@ functions needed for the mob to work properly which contains the following:
    'fall_damage'   when true causes falling to inflict damage.
    'water_damage'  holds the damage per second infliced to mobs when standing in
                    water.
+   'air_damage'    holds damage per second inflicted to mob when standing in air.
    'lava_damage'   holds the damage per second inflicted to mobs when standing
                    in lava or fire or an ignition source.
    'light_damage'  holds the damage per second inflicted to mobs when light
@@ -299,6 +300,9 @@ enhance mob functionality and have them do many interesting things:
                     is returned normal attack function continued.
    'on_die'         a function that is called when mob is killed (self, pos), also
                     has access to self.cause_of_death table.
+   'on_flop'        function called when flying or swimmimng mob is no longer in
+                    air/water, (self) paramater and return true to skip the built
+                    in api flop feature.
    'do_custom'      a custom function that is called every tick while mob is
                     active and which has access to all of the self.* variables
                     e.g. (self.health for health or self.standing_in for node
diff --git a/readme.MD b/readme.MD
index 1382810..67cc12b 100644
--- a/readme.MD
+++ b/readme.MD
@@ -23,7 +23,7 @@ Lucky Blocks: 9
 
 
 Changelog:
-- 1.54 - Simplified animal breeding function, added editable settings (thanks Wuzzy), Child mobs now take 20 mins to grow up, reverted to simple mob spawning with setting to use area checks.
+- 1.54 - Simplified animal breeding function, added editable settings (thanks Wuzzy), Child mobs now take 20 mins to grow up, reverted to simple mob spawning with setting to use area checks, on_flop added, air_damage added.
 - 1.53 - Added 'on_map_load' settings to mobs:spawn so that mobs will only spawn when new areas of map are loaded.
 - 1.52 - Added 'mob_active_limit' in settings to set number of mobs in game,
 (default is 0 for unlimited), removed {immortal} from mob armor, fluid viscocity slows mobs