What a nice pattern.
While shown in a Christmas setting, it certainly would be a nice wintry quilt, or even all year long.
The flying geese would be made in the same manner, except you have the overlap at the top to give that bigger sky/background space. You could do it by traditional piecing, by snowballing the corners (in a sense). I see that is the way they have done the top of the tree.
Another way would be to make QSTs with 3-sections in the background, then cut off the excess to make your rectangle. Though, to me, that would be a lot of work, to do and then cut off.
If it were me, the quickest and easiest way would be draw it all out on graph paper, and make the geese as PP units.
After that, then join it together with a whole bunch of HSTs.
Not that I need another idea ...... but............. yes, you just gave me another one!
