According to Hanks & Hodges'
A Dictionary of Surnames, Alaire and Allaire are French surnames derived from the given name
Hilary (which was male in medieval times). Alair is an American family name, perhaps an alteration of Alair or Allaire.
All three of these surname spellings have been used for names of characters or places in fantasy novels or games. One of the best known examples is the novel
The Ring of Allaire by
Susan Dexter, originally published in 1985.