We did the motions the same, as I remember, but our (camp) version went thus:

Up in the air Junior Birdmen,
Up in the air, upside down (yeeown!)
Up in the air, Junior Birdmen,
And keep your noses off the G-R-O-U-N-D ground.

When you hear the mailman's whistle,
And you see their wings of tin (eeyown!)
Then you will know the Junior Birdmen
Have sent their box tops in, tra la,
Have sent their box tops in, tra la,
Have
sent
    their
       box
          tops
             in!