As explained in History and Origins of the Hippogriff, the idea of mating gryphons with mares in Virgil represents an impossible scenario. So, what then does the hippogriff symbolise in Orlando Furioso? That’s a very good question— and I’ve yet to come up with a concise answer. Critical responses to the hippogriff in Orlando tend to offer complex and varied answers and interpretations. Some suggest it’s related to "the natural appetites" , "ascent"  or "poetic fame" . My favourite was a lengthy explanation of how the hippogriff is a "sliding signifier"  which is a jargon way of saying "it really means a whole lot of things and we can’t really pin it down."
Several online sources suggest that the hippogriff is associated with love. Some sites characterise it as "impossible love," as that’s how the image is used in Virgil. The sources which suggest that it simply means "love" rarely explain why and several are not reliable to one extent or another (please see Bibliography for a complete list of print and online sources consulted). However there are indeed some written sources which suggest that hippogriffs represent love. One site quotes Joe Nigg’s The Book of Gryphons. In this book, Nigg suggests that Ariosto "joins the two [gryphons and horses] as a symbol of love" . The Larousse Dictionary of World Folklore suggests something similar but, again, does not explain why .
Though I must admit I was originally somewhat sceptical, I do now believe that the hippogriff can be interpreted as representing love for a couple of different reasons. The first is the hippogriff’s unusual parentage, the idea being that, through love, the griffon and the horse are able to overcome even the obstacle of their being enemies. There has also been the suggestion that the hippogriff is a metaphor for love because of flight. An online article on Canadian heraldry suggests of the hippogriff that "commentators on this work [Orlando Furioso] claim that it is a metaphor for love, being able to transport men and women" . Similarly, another dictionary of symbol suggested that the hippogriff is used "as a symbol of love, presumably, because of its soaring habit and fantastic gleaming appearance" .These explanations suggests a certain logic to the interpretation of the hippogriff as a metaphor for love since it ties the act of flight with the feeling of love. Thus it is indeed possible to interpret the hipporgiff as a metaphor for love, although it can have other associations as well, such as imaginative or spiritual ascent.
 Wiggins, quoting Toscanella.
Peter DeSa Wiggins, Figures in Ariosto Tapestry: Character and Design in the Orlando Furioso (Baltimore: Johns Hopkins UP 1986) 12.
 Marianne Shapiro, The Poetics of Ariosto (Detroit: Wayne State UP, 1988) 22.
 Marianne Shapiro, The Poetics of Ariosto (Detroit: Wayne State UP, 1988) 116-7.
 Albert Russell Ascoli, Ariosto’s Bitter Harmony: Crisis and Evasion in the Italian Renaissance (Princeton, N.J.: Princeton UP 1987) 249.
 Joe Nigg, The Book of Gryphons, Bard Woodcrafts “Magical Beasts,” 22 Feb. 2005 http://bardwood.com/BEASTS.HTML
 Alison Jones, "hippogriff," Larousse Dictionary of World Folklore (Edinburgh: Larousse, 1995)
 Darren S.A. George, "The Mad Menagerie," Heraldry in Canada 10 June 2004 http://www.hsc.ca/Archives/mad1.html
 Pamela Allardice, Myths and Gods and Fantasy (Santa Barbara: ABC-CLIO, 1991) 114.