If people are curious, I just went through the CIC game guides and counted up the number of times you fly each and every ship.
I only counted the "main" games and their addons: WC1, SM1+2, WC2, SO1+2, WC3, WC4, WCP, SecretOps. Also, if the same ship was flyable in multiple games, even if it was an updated version or model (e.g. the WC1 and WC2 Rapier II's, or the P64 Ferret and P64C Super Ferret), I counted them as the same fighter (just as I would consider the P-51B and P51D Mustangs to be the same fighter). There are nine such ships. I counted the total number of missions (both losing and winning tracks) you were required to or had the option of flying the fighter. Here's the tallies:
Rapier (WC1+2 version) 31
Ferret (including the "Super Ferret") 12
Epee 6 (Thank goodness!)
Wasp (including "Black" version) 9
Panther (including "Black" version) 40
Shrike (including "Black" version) 17 (waaaay to many)
Vampire (including "Black" version) 15
Devastator (including "Black" version) 12
Note that I think the game guides were a little wrong for some of the WC4 missions...they say you can only choose the Dragon for a few missions (like the Ella starbase mission), when I am quite certain (and the posts in the game guides agree with my memory) that you can pick other fighters, especially the Bearcat. I know this because I think I am the only person on the planet that actually perfers the Bearcat to the Dragon and would pick it whenever available.
So whoever said the Dralthi was the least flown fighter, at least by the player, was almost right. It turns out that the little Pirahna beats it out, with only 3 mission appearances to the Dralthi's 4. Just as well, considering it didn't have enough guns to actually shoot anything down.
The most flown fighter was the Panther, with 40 mission appearances, barely beating out the good old Hellcat V, with 39 possible appearances. However, the Panther actually probably beats the Hellcat by more, considering that Prophecy and SecretOps don't let you choose your fighter (unless you hack the game to do so...now that would be an fan project...can you imagine the challenges we could offer to one another--Beat the entire game except the strike missions flying a Tigershark!). So most people probably fly the Hellcat a lot less.
Oh, and I agree that the Dralthi is the face of the series, although the Rapier or the Hellcat wouldn't be a bad choice based on the number of times you fly the things. I also disagree that the Raptor had a distinctive shape...it always looked to me as if the game designers were heavily inspired by the Rylan Gunstar (from "The Last Starfighter") when they came up with that ship.