I made the boys 4th of July shirts, even though I was up pretty late the night before making them, I'm glad I did it! I made B and P's from scratch but not C's I already had a white shirt for him.
B's shirt turned out good and I made it in about an hour minus the applique.
For the flag I cut it out of an old shirt and hand sewed it on.
C's shirt
I used plain white muslin for the stars and hand sewed them in place.
P's shirt
I embroidered X's for the stars, I think it's my favorite one I did.
A tip for sewing applique's on knit fabric it to use stick glue to put them where you want. It washes right out, it stiffens when dry making sewing easier and you don't need to pin it!