A flying geese unit is made from three triangles that, when sewn together, form a rectangle.
Skill Builder: Here's a quick block that uses eight flying geese units
Requirements: a rotary cutter, cutting mat and acrylic ruler, scrap fabric.
Cut TWO pieces of scrap fabric 5-1/4" square. Cut the square on the diagonal TWICE (see first photo below).
Cut EIGHT pieces of scrap fabric 2-7/8" square. Cut the square on the diagonal ONCE (see first photo below).
The picture below shows HALF of the fabric requirement:
2. To begin the unit, lay out one large triangle (the "body") with two small triangles (the "wings") in the upper corners:
3. Fold down the left "wing" so that the bottom edges of the two triangles align and the fabric is right-sides together:
4. Sew with the "wing" triangle on top. Sew along the short edge of the "body" triangle:
5. Iron the seam toward the "wing" triangle and trim off the two dog ears:
6. Next, fold down the right "wing" triangle so that the bottom of the two triangles align:
7. This time sew with the BODY on top. Sew along the short edge of the "body" triangle:
8. Press toward the "wing" and trim off the dog ears. The resulting rectangle should measure 2-1/2" x 4-1/2":
9. Repeat the above steps until you have EIGHT flying geese units. Lay them out in a pattern you like. Below is the one I chose: 
10. Next, join the flying geese units to each other: Align two units and and sew with a 1/4" seam. The 1/4" seam should land just OUTSIDE the point where the "V" of the "body" joins the "wings." If the 1/4" seam falls INSIDE the intersection, the point is lost so slow down and pay attention!!! 
12. Finally, join the sets of flying geese units together:
