If you don't mind using a helper column you could enter this formula into the helper cells starting, say, on row-2

=IF(ISEVEN(ROW()),ROW(),""), copied down the column

The formula returns the row number if the row number is even

Let's say we use colum-C as the helper and we want to pull the data into column-D

In D2, copied down: =INDEX(A2:A100,MATCH(SMALL(C2:C100,ROW(A1)),C2:C10 0,0))
This pull values from every other row into column-A into column-D

To get column-B values into, say, column-E
In E2: =INDEX(B2:B100,MATCH(SMALL(C2:C100,ROW(A1)),C2:C10 0,0))

If the start row of your data begins on an odd numbered row, then use ISODD in place of ISEVEN.
Afterward, copy the D:E cells and paste back as values only then delete the helper cells.