Flights and tall buildings or mountains are some of the best ways to see a different class of atmospheric optical phenomena, namely those which lie opposite to the sun. In the images below, diffraction in the cloud droplets produces a multi-ringed glory that surrounds the shadow of the airplane.
With the clouds slightly farther away, the shadow of the airplane gets smaller in respect to the size of the glory, which remains roughly constant.
Sometimes, when one can see a glory, the conditions are right also for producing a cloudbow (a type of fogbow) farther away from the airplane's shadow. A few supernumerary arcs are also visible in the image, on the inside of the main cloudbow arc.
Some similar images of mine were published as the Optics Picture of the Day some time ago.