AWS D17.1 is the specification for aerospace fusion welding.
It is common for 1G tests to be done in aerospace welding certification because shops often have positions and manipulators that can pretty much get every weld in the flat position.
But sometimes employers require a 2G and or a 3G test for a broader qualification.
This demonstration is a practice weld using 304L stainless in .063” thickness.
Other alloys like 17-7ph or 15-7ph would be more common in aerospace but practicing on 304L stainless helps anyway and is a lot cheaper.