The latest aircraft targetted by Sonic Solutions as needing a replacement sound set is the F/A-18 Hornet – examples of which can be found freeware, in the MS Acceleration add-on pack and as payware. This pack is advertised as being suitable for all of them in FSX or Prepar3D.
Presented as 48k/16 bit files, the soundpack features both internal and external sounds, using the ‘sound cone’ technology that is part of the FSX family of simulators. It also includes AI sound sets, for use by, obviously, AI aircraft, but also other pilots’ aircraft in multiplayer sessions. A number of the sound files will be played randomised, so hopefully no two flights will sound exactly the same.
See here for full details and to purchase.