Here is how I made them...
Cut the the layers out on my cricut, red background layer (which if you look closely you'll see also has an oval cut out to help me thread them evenly), the white layer and then the blue letters.
Then I assembled the individual banners:
Then I flipped them over to reveal the guide on the red layer that was cut by the Cricut so that each pennant would have their slits cut in exactly the same spot - what I tried and discovered didn't work was to precut the slit in both layers.
Why didn't that work? First, lining the two slits up perfect was a challenge, and second, the cricut couldn't get the slit as narrow as I wanted it - too wide of a slit and the pennants slide around on the ribbon and gravity is not the friend of the garland.
So I cut them by hand.
And then I threaded them onto the ribbon, first trying and not liking them on white, then loving them on red.
And that was it - 3 fabulous custom paper pennant garlands for his room.