Add following to IMove.

OpenRA.Mods.RA/Activities/FlyFollow.cs

@@ -0,0 +1,44 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2014 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation. For more information,
+ * see COPYING.
+ */
+#endregion
+
+using OpenRA.Mods.RA.Air;
+using OpenRA.Mods.RA.Move;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.RA.Activities
+{
+	public class FlyFollow : Activity
+	{
+		Target target;
+		Plane plane;
+		WRange range;
+
+		public FlyFollow(Actor self, Target target, WRange range)
+		{
+			this.target = target;
+			plane = self.Trait<Plane>();
+			this.range = range;
+		}
+
+		public override Activity Tick(Actor self)
+		{
+			if (IsCanceled || !target.IsValidFor(self))
+				return NextActivity;
+
+			if (target.IsInRange(self.CenterPosition, range))
+			{
+				Fly.FlyToward(self, plane, plane.Facing, plane.Info.CruiseAltitude);
+				return this;
+			}
+
+			return Util.SequenceActivities(new Fly(self, target, WRange.Zero, range), this);
+		}
+	}
+}