diff --git a/OpenRa.DataStructures/float2.cs b/OpenRa.DataStructures/float2.cs
index 7377c9ea59..b905791e59 100644
--- a/OpenRa.DataStructures/float2.cs
+++ b/OpenRa.DataStructures/float2.cs
@@ -25,7 +25,7 @@ namespace OpenRa
 
 		public static float2 operator -(float2 a) { return new float2(-a.X, -a.Y); }
 
-		static float Lerp(float a, float b, float t) { return a + t * (b - a); }
+		public static float Lerp(float a, float b, float t) { return a + t * (b - a); }
 
 		public static float2 Lerp(float2 a, float2 b, float t)
 		{
diff --git a/OpenRa.Game/Actor.cs b/OpenRa.Game/Actor.cs
index f440962df6..ff765c9edb 100755
--- a/OpenRa.Game/Actor.cs
+++ b/OpenRa.Game/Actor.cs
@@ -88,6 +88,7 @@ namespace OpenRa.Game
 
 			var underCursor = Game.UnitInfluence.GetUnitAt( xy ) 
 				?? Game.BuildingInfluence.GetBuildingAt( xy );
+
 			if (underCursor != null && !underCursor.Info.Selectable)
 				underCursor = null;
 
diff --git a/OpenRa.Game/Effects/Bullet.cs b/OpenRa.Game/Effects/Bullet.cs
index 3f47590d5e..1243626f63 100644
--- a/OpenRa.Game/Effects/Bullet.cs
+++ b/OpenRa.Game/Effects/Bullet.cs
@@ -15,6 +15,8 @@ namespace OpenRa.Game.Effects
 		readonly int2 Src;
 		readonly int2 Dest;
 		readonly int2 VisualDest;
+		readonly int SrcAltitude;
+		readonly int DestAltitude;
 
 		int t = 0;
 		Animation anim;
@@ -23,7 +25,7 @@ namespace OpenRa.Game.Effects
 
 		/* src, dest are *pixel* coords */
 		public Bullet(string weapon, Player owner, Actor firedBy, 
-			int2 src, int2 dest)
+			int2 src, int2 dest, int srcAltitude, int destAltitude)
 		{
 			Owner = owner;
 			FiredBy = firedBy;
@@ -55,7 +57,8 @@ namespace OpenRa.Game.Effects
 			if (t > TotalTime())		/* remove finished bullets */
 			{
 				Game.world.AddFrameEndTask(w => w.Remove(this));
-				Combat.DoImpact(Dest, VisualDest, Weapon, Projectile, Warhead, FiredBy);
+				Combat.DoImpact(Dest, VisualDest - new int2( 0, DestAltitude ), 
+					Weapon, Projectile, Warhead, FiredBy);
 			}
 		}
 
@@ -65,17 +68,17 @@ namespace OpenRa.Game.Effects
 		{
 			if (anim != null)
 			{
-				var pos = float2.Lerp(
-						Src.ToFloat2(),
-						VisualDest.ToFloat2(),
-						(float)t / TotalTime()) - 0.5f * anim.Image.size;
+				var at = (float)t / TotalTime();
+
+				var altitude = float2.Lerp(SrcAltitude, DestAltitude, at);
+				var pos = float2.Lerp( Src.ToFloat2(), VisualDest.ToFloat2(), at)
+					- 0.5f * anim.Image.size - new float2( 0, altitude );
 
 				if (Projectile.High || Projectile.Arcing)
 				{
 					if (Projectile.Shadow)
 						yield return new Renderable(anim.Image, pos, 8);
 
-					var at = (float)t / TotalTime();
 					var highPos = pos - new float2(0, (VisualDest - Src).Length * height * 4 * at * (1 - at));
 
 					yield return new Renderable(anim.Image, highPos, Owner.Palette);
diff --git a/OpenRa.Game/Effects/Missile.cs b/OpenRa.Game/Effects/Missile.cs
index f1e1fc2267..ee5d2ce88a 100644
--- a/OpenRa.Game/Effects/Missile.cs
+++ b/OpenRa.Game/Effects/Missile.cs
@@ -2,6 +2,7 @@
 using OpenRa.Game.GameRules;
 using OpenRa.Game.Graphics;
 using OpenRa.Game.Traits;
+using System;
 
 namespace OpenRa.Game.Effects
 {
@@ -17,9 +18,10 @@ namespace OpenRa.Game.Effects
 		readonly Animation anim;
 		int Facing;
 		int t;
+		int Altitude;
 
 		public Missile(string weapon, Player owner, Actor firedBy,
-			int2 src, Actor target)
+			int2 src, Actor target, int altitude)
 		{
 			Weapon = Rules.WeaponInfo[weapon];
 			Projectile = Rules.ProjectileInfo[Weapon.Projectile];
@@ -28,6 +30,7 @@ namespace OpenRa.Game.Effects
 			Owner = owner;
 			Target = target;
 			Pos = src.ToFloat2();
+			Altitude = altitude;
 
 			/* todo: initial facing should be turret facing, or unit facing if we're not turreted */
 			Facing = Traits.Util.GetFacing( Target.CenterLocation - src.ToFloat2(), 0 );
@@ -50,6 +53,10 @@ namespace OpenRa.Game.Effects
 		{
 			t += 40;
 
+			var targetUnit = Target.traits.GetOrDefault<Unit>();
+			var targetAltitude = targetUnit != null ? targetUnit.Altitude : 0;
+			Altitude += Math.Sign(targetAltitude - Altitude);
+
 			Traits.Util.TickFacing(ref Facing, 
 				Traits.Util.GetFacing(Target.CenterLocation - Pos, Facing),
 				Projectile.ROT);
@@ -70,7 +77,7 @@ namespace OpenRa.Game.Effects
 			Pos += move;
 
 			if (Projectile.Animates)
-				Game.world.AddFrameEndTask(w => w.Add(new Smoke((Pos - 1.5f * move).ToInt2())));
+				Game.world.AddFrameEndTask(w => w.Add(new Smoke((Pos - 1.5f * move - new int2( 0, Altitude )).ToInt2())));
 
 			// todo: running out of fuel
 			// todo: turbo boost vs aircraft
@@ -78,7 +85,7 @@ namespace OpenRa.Game.Effects
 
 		public IEnumerable<Renderable> Render()
 		{
-			yield return new Renderable(anim.Image, Pos - 0.5f * anim.Image.size, 0);
+			yield return new Renderable(anim.Image, Pos - 0.5f * anim.Image.size - new float2(0, Altitude), 0);
 		}
 	}
 }
diff --git a/OpenRa.Game/Game.cs b/OpenRa.Game/Game.cs
index bc1bd8a468..6fa6741559 100644
--- a/OpenRa.Game/Game.cs
+++ b/OpenRa.Game/Game.cs
@@ -224,7 +224,7 @@ namespace OpenRa.Game
 					Rules.TileSet.GetWalkability(Rules.Map.MapTiles[a.X, a.Y])) < double.PositiveInfinity;
 		}
 
-		static IEnumerable<Actor> FindUnits(float2 a, float2 b)
+		public static IEnumerable<Actor> FindUnits(float2 a, float2 b)
 		{
 			var min = float2.Min(a, b);
 			var max = float2.Max(a, b);
diff --git a/OpenRa.Game/Traits/AttackBase.cs b/OpenRa.Game/Traits/AttackBase.cs
index f558267770..44b0763a5c 100644
--- a/OpenRa.Game/Traits/AttackBase.cs
+++ b/OpenRa.Game/Traits/AttackBase.cs
@@ -105,19 +105,23 @@ namespace OpenRa.Game.Traits
 			}
 
 			var firePos = self.CenterLocation.ToInt2() + Util.GetTurretPosition(self, unit, offset, 0f).ToInt2();
-			var thisTarget = target;
+			var thisTarget = target;	// closure.
+			var destUnit = thisTarget.traits.GetOrDefault<Unit>();
 
 			ScheduleDelayedAction(self.Info.FireDelay, () =>
 			{
+				var srcAltitude = unit != null ? unit.Altitude : 0;
+				var destAltitude = destUnit != null ? destUnit.Altitude : 0;
+
 				if( weapon.RenderAsTesla )
 					Game.world.Add( new TeslaZap( firePos, thisTarget.CenterLocation.ToInt2() ) );
 
 				if( Rules.ProjectileInfo[ weapon.Projectile ].ROT != 0 )
 					Game.world.Add(new Missile(weaponName, self.Owner, self,
-						firePos, thisTarget));
+						firePos, thisTarget, srcAltitude));
 				else
 					Game.world.Add(new Bullet(weaponName, self.Owner, self,
-						firePos, thisTarget.CenterLocation.ToInt2()));
+						firePos, thisTarget.CenterLocation.ToInt2(), srcAltitude, destAltitude));
 
 				if (!string.IsNullOrEmpty(weapon.Report))
 					Sound.Play(weapon.Report + ".aud");
diff --git a/OpenRa.Game/Traits/Explodes.cs b/OpenRa.Game/Traits/Explodes.cs
index 7392d08712..f19726d48d 100644
--- a/OpenRa.Game/Traits/Explodes.cs
+++ b/OpenRa.Game/Traits/Explodes.cs
@@ -14,9 +14,13 @@ namespace OpenRa.Game.Traits
 		{
 			if (self.IsDead)
 			{
+				var unit = self.traits.GetOrDefault<Unit>();
+				var altitude = unit != null ? unit.Altitude : 0;
+
 				Game.world.AddFrameEndTask(
 					w => w.Add(new Bullet("UnitExplode", e.Attacker.Owner, e.Attacker,
-						self.CenterLocation.ToInt2(), self.CenterLocation.ToInt2())));
+						self.CenterLocation.ToInt2(), self.CenterLocation.ToInt2(),
+						altitude, altitude)));
 			}
 		}
 	}
diff --git a/units.ini b/units.ini
index a799760dae..7eb75c5745 100755
--- a/units.ini
+++ b/units.ini
@@ -238,7 +238,7 @@ InitialFacing=50
 LongDesc=Anti-Armor base defense.\n  Strong vs Tanks\n  Weak vs Infantry, Aircraft
 [AGUN]
 Description=AA Gun
-Traits=Building, Turreted, RenderBuildingTurreted
+Traits=Building, Turreted, RenderBuildingTurreted, AttackTurreted, AutoTarget
 Dimensions=1,2
 Footprint=_ x
 SelectionPriority=3
@@ -260,7 +260,7 @@ SelectionPriority=3
 LongDesc=Regenerates the Fog of War nearby, \nobscuring the area.\n  Unarmed
 [SAM]
 Description=SAM Site
-Traits=Building, Turreted, RenderBuildingTurreted
+Traits=Building, Turreted, RenderBuildingTurreted, AttackTurreted, AutoTarget
 Dimensions=2,1
 Footprint=xx
 SelectionPriority=3