I enjoy @gray's work on aircraft but, to be honest, I think his backdrops rarely get as much recognition.
Have a look at https://www.talkgraphics.com/search....rchid=18546752.

@gray mentions his cloud making and backgroud was from vector and then touched up: https://www.talkgraphics.com/showthr...550#post644550.

I thought of making cloud all within Xara.

In XPro+ & XDPX, we have the Brush Tool.
In my design, I make an oval with Feathering and a Fractal Cloud Fill.
I used this as my brush graphic (bottom-right).
The Brush is a Scatter brush and I further edited with some randomness applied to the Spacing & Offset.
I include a Transparency at this point.

I then just scribbled some twisting lines as shown in the locked Info layer.

The clever bit is when you then squeeze or stretch the 'cloud' or change the Line width: the cloud transforms as if the cloud was real and in quick time.
Changing the Transparancy of some of the cloud achieves darkening, lightening and even colour edging.

Not saying my design is a masterpiece, I'll leave that to yourselves.

Xara - Cloud Maker.xar

Acorn