A Strange Phenomenon: Rainbow / Halo around airplane's shadow

[BIAD]

The glass may be the reason but still need a clearer explanation.
It looked way too intriguing and that is why I am curious to know the exact reason behind this unusual phenomenon.

This may assist.

Glory (optical phenomenon)


'A glory is an optical phenomenon that resembles an iconic saint's halo about the shadow of the observer's head,
caused by light of the Sun or (more rarely) the Moon interacting with the tiny water droplets that make up mist or clouds.

The glory consists of one or more concentric, successively dimmer rings, each of which is red on the outside and bluish
towards the centre. Due to its appearance, the phenomenon is sometimes mistaken for a circular rainbow, but the latter
has a much larger diameter and is caused by different physical processes.

Glories arise due to wave interference of light internally refracted within small droplets...'
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