diff --git a/openttd.dsp b/openttd.dsp
--- a/openttd.dsp
+++ b/openttd.dsp
@@ -103,6 +103,10 @@ SOURCE=.\ai\default.c
 # End Source File
 # Begin Source File
 
+SOURCE=.\ai\ai.c
+# End Source File
+# Begin Source File
+
 SOURCE=.\ai\trolly\pathfinder.c
 # End Source File
 # Begin Source File
@@ -498,6 +502,10 @@ SOURCE=.\ai\trolly\trolly.h
 # End Source File
 # Begin Source File
 
+SOURCE=.\ai\ai.h
+# End Source File
+# Begin Source File
+
 SOURCE=.\aystar.h
 # End Source File
 # Begin Source File