(Full disclosure: I was asked to write for the newspaper several years ago, but the stint ended after one article when the editors realized I am not a conspiracy theorist and would not pretend false theories were true.)
The idea of angels as aliens is of course a well-worn trope in ancient astronaut circles. Erich von Däniken discussed the idea in the 1960s and 1970s. This all traces its origin to the idea that the Fallen Angels (the Nephilim) from Genesis 6 were extraterrestrials, based on a reading of the passage with its amplification in the first-century BCE apocryphal Book of Enoch, which discusses the history of the Watchers in great detail.
Of course, if these Watchers really were aliens, they sure had funny priorities:
And Azâzêl taught men to make swords, and knives, and shields, and breastplates, and made known to them the metals <of the earth> and the art of working them, and bracelets, and ornaments, and the use of antimony, and the beautifying of the eyelids, and all kinds of costly stones, and all colouring tinctures. (1 Enoch 8:1)
Some time after Enoch was written, there was also written the Book of Giants which told more about the Nephilim and their offspring, the giants, but, tellingly, Giants is dependent upon and younger than Enoch, which in turn is younger than and dependent upon Genesis. If the material contained in Enoch and Giants were a genuine report of early alien intervention, we should find the same material in both texts, as well as Genesis. But the fact is that Giants contains material found in Enoch and Genesis, while Enoch contains material found only in Genesis but not Giants, and Genesis has nothing of either Giants or Enoch except what all three share in common. The obvious conclusion is that the later books were fictional additions to the earliest legends embodied in Genesis.