From Worksheets to Master Worksheet
Constants Version
Sub CopyToMaster()
    Const cSource1 As String = "Sheet3"  ' 1st Source Worksheet Name
    Const cSource2 As String = "Sheet4"  ' 2st Source Worksheet Name
    Const cTarget As String = "Sheet5"   ' Target Worksheet
    Const cRange As String = "A3"        ' First Cell Address of Copy Range
    Const cCol As Long = 1               ' Target Column Number
    Dim ws1 As Worksheet  ' 1st Source Worksheet
    Dim ws2 As Worksheet  ' 2nd Source Worksheet
    Dim wsT As Worksheet  ' Target Worksheet
    Dim Rng As Range      ' Copy Range (in 1st and 2nd Source Worksheet)
    Dim FNR As Long       ' First Not Used Row
    ' Create references to all Worksheets
    With ThisWorkbook
        Set ws1 = .Worksheets(cSource1)
        Set ws2 = .Worksheets(cSource2)
        Set wsT = .Worksheets(cTarget)
    End With
    ' Calculate First Not Used Row in Target Column.
    FNR = wsT.Cells(wsT.Rows.Count, cCol).End(xlUp).Offset(1).Row
    ' Calculate Copy Range in 1st Source Worksheet
    Set Rng = ws1.Range(ws1.Range(cRange), ws1.Range(cRange).End(xlDown))
    ' Copy Copy Range in 1st Source Worksheet to Target Column.
    Rng.Copy wsT.Cells(FNR, cCol)
    ' Calculate First Not Used Row in Target Column.
    FNR = wsT.Cells(wsT.Rows.Count, cCol).End(xlUp).Offset(1).Row
    ' Calculate Copy Range in 2nd Source Worksheet
    Set Rng = ws2.Range(ws2.Range(cRange), ws2.Range(cRange).End(xlDown))
    ' Copy Copy Range in 2nd Source Worksheet to Target Column.
    Rng.Copy wsT.Cells(FNR, cCol)
End Sub
'I Hate Constants' Version
Sub IHateConstants()
    Dim ws1 As Worksheet  ' 1st Source Worksheet
    Dim ws2 As Worksheet  ' 2nd Source Worksheet
    Dim wsT As Worksheet  ' Target Worksheet
    Dim Rng As Range      ' Copy Range (in 1st and 2nd Source Worksheet)
    Dim FNR As Long       ' First Not Used Row
    ' Create references to all Worksheets
    With ThisWorkbook
        Set ws1 = .Worksheets("Sheet3")
        Set ws2 = .Worksheets("Sheet4")
        Set wsT = .Worksheets("Sheet5")
    End With
    ' Calculate First Not Used Row in first column of Target Worksheet.
    FNR = wsT.Cells(wsT.Rows.Count, 1).End(xlUp).Offset(1).Row
    ' Calculate Copy Range in 1st Source Worksheet
    Set Rng = ws1.Range(ws1.Range("A3"), ws1.Range("A3").End(xlDown))
    ' Copy Copy Range in 1st Source Worksheet to first column of Target
    ' Worksheet.
    Rng.Copy wsT.Cells(FNR, 1)
    ' Calculate First Not Used Row in first column of Target Worksheet.
    FNR = wsT.Cells(wsT.Rows.Count, 1).End(xlUp).Offset(1).Row
    ' Calculate Copy Range in 2nd Source Worksheet
    Set Rng = ws2.Range(ws2.Range("A3"), ws2.Range("A3").End(xlDown))
    ' Copy Copy Range in 2nd Source Worksheet to first column of Target
    ' Worksheet.
    Rng.Copy wsT.Cells(FNR, 1)
End Sub