There was a Pitts Model 12 operated at White Waltham fitted with air horns. Alan Cassidy used to do a low flypast at extremely high alpha, tooting the horns, very amusing. Otherwise, I think the police use a shouty thing on some aircraft, but you'd probably not really be able to make out what they're saying while you're running from justice.
Seriously, what would the point be in real life. Most aircraft make a significant racket to attract attention, anyway. Hopefully you shout 'CLEAR!' loudly enough to wake the dead before starting...
TOO