I think that AixConan is only a fantasm that some fans have. I mean it's obvious that Shinichi loves Ran and vice versa. Ran is contantly worrying about Shinichi, and not to mention, always embarassed when Sonoko teases her about her feelings toward Shinichi.
And Shinichi is always deeply touched when he realizes this.
Finally Shinichi confessed his love Ran around episode 621 or something like that.