Generating Multiple Textboxes With Relative Position

I am trying to create a form with a text box that when text is entered, it adds to the userform another textbox with that data in it. The focus then goes back to the original textbox so that more may be added indefinitely, all with relative position to the most recently added textbox. Here is what I have so far, works for one time, but not multiple textboxes. The original textbox is "txtAPID"

Private Sub MakeNewTextBox()
Dim newTextBox As TextBox
Dim ControlTop As Long
With LastAirport
ControlTop = 30
End With
Set newTextBox = Me.Controls.Add("Forms.TextBox.1", "txtNextAirport", True)
With newTextBox
.Left = 20
.Top = ControlTop + 3
.Height = 15
.Text = txtAPID.Text
End With....................