Regarding those that argue that "wouldn't we see ripples" if the plane were a boat, I don't think that you would expect to see the same kind of easily visible ripples seen in images of boats that have been posted. There is great difference in photo quality of these images, that would affect the visibility of ripples, not to mention the very different properties of what is being reflected.
Just reducing the boat in the image below to roughly the width of the plane in the Calvine photo makes the ripples from JMartJr's image (left most small sub-image) harder to see. When I added a small amount of blur in Photoshop (Gausian blur of 1.0), to mimic the fuzziness of the photo in the OP (middle sub-image), the ripples almost disappear. To get the contrast similar to that of the Calvine photo, I adjusted the levels to increase the black level and the ripples are pretty much gone.
This doesn't even address the differences in what is being reflected, which in the case of the boat photo above is a high contrast mix of blue sky and white cloud, with clearly visible sunrise/sunset directional lighting, plus high mountains all around, contrasting strongly against the sky.
Whereas the Calvine photo shows a sky (assuming that it is a sky) that is much lower contrast, has much less variation in brightness, no distinct structures and is basically a fuzzy gradient from top left, to bottom right.
With that kind of reflection and the low quality and small size of the "man in the boat", if that man was rowing full pelt, then I doubt that any ripples would be visible.
For a cloudy sky comparison, here is a photo I took of a small boat that's very large in the frame, on a lake, under a sky of heavy cloud. There is rippling visible, but it's not particularly pronounced, even at this size. Reducing that boat down to the size of the Calvine plane (uppermost cutout image below the Calvine object) and the ripples have gone, even before adding a small blur (the lower cutout image).
One last point is that just because there is a man in a boat, that doesn't mean that the boat is in motion and causing ripples, for example if the person in the boat was fishing.