Almost every special you see on TV regarding the history of Unidentified Flying Objects (UFO's) inevitably cites Orthodox icons as proof that the Romans at least believed in UFO's or alien spacecraft. Of course, for everyone that knows the basic method of intepretating Orthodox icons, this is clearly not the case and is a total misrepresentation of the basic interpretation of Byzantine iconography.
For example, the icon shown in the video above from Decani Monastery of the Crucifixion of Christ does not depict alien spacecraft, but personifications of the sun and the moon. Ancient art, especially Greek and Roman, often personified such things as water, the sun, the moon, the earth, the planets, virtues, vices, and other such things. This is because in languages like Greek they take on either a feminine or masculine name. For example, the Greek word for sun is masculine and the word for earth is feminine; in iconography they would thus be depicted as male for the former and female for the latter. Regarding the icon of the Crucifixion, when the Gospels say the sun was darkened at the Crucifixion of Jesus, in Greek it thus reads as if the sun is a male person who hid its light, and in this way it is depicted.
Are there any traces of UFO's in Orthodox iconography? The answer is emphatically NO! Everything cited by paranormal "experts" as depictions of UFO's in icons is bogus and based on unwarranted ignorance. It goes back to the hugely successful book Chariots of the Gods written in 1968 by Erich von Däniken.