Here are 2 more aircraft designs. I call them sketches as they’re not finished pieces but they are cleaned up with the rough lines removed. The obvious advantage of drawing digitally is the time saved as there’s no need to scan from my sketchpad plus you can improvise and alter the canvas size to fit the drawing.
The first is a fighter jet type craft.
The second is a cruiser the tiny dot under the shadow represents the scale to 1 person. This is a basic drawing which is quick to do but still shows the form of the craft without having to draw too much detail. I find this ideal when playing with different shapes to create things. I find it easier sometimes starting with a dark block and deleting areas out instead of drawing dark lines on a white background.