Sub es()
Dim m As Object, k
Set m = CreateObject("scripting.dictionary")
For Each k In Feuil1.Range("a2:a" & Feuil1.Cells(Rows.Count, 1).End(3).Row)
m(k.Value) = ""
Next k
For Each k In Feuil2.Range("a2:a" & Feuil2.Cells(Rows.Count, 1).End(3).Row)
m(k.Value) = ""
Next k
Feuil3.[a2].Resize(m.Count, 1) = Application.Transpose(m.keys)
End Sub