The shape makes me think of a flying seagull.
But take a moment to look carefully – the backdrop to these clouds is the Atlantic Ocean and not the sky!! Another in my series World from Above

“I’ve looked at clouds from both sides now
From up and down, and still somehow
It’s cloud illusions I recall
I really don’t know clouds at all”
Joni Mitchell – Both Sides Now

Nikon D200, Sigma 18-200mm.
Location: 11,000 metres above the Atlantic Ocean, off the north African coast, en route for the Canary Islands.

Article in September Edition of Wildlife, Nature and Landscape Photography Online Magazine – Capturing the World from Above – Tips for Aerial Photography