The Havoc, the Raven's Claw and the Stinger are models made with an old modding mentality.
I mean, 2-4 years ago, in popular mods (Mikes TBB and Asgard mod come to mind) you could see all those plane-ish kind of ships. There were few modellers dedicated to quality and keeping things "Freelancerish". Many models where either adaptations from random models on the net, or poorly designed.
It was the golden era of Freelancer multiplayer, many people on servers, everyone was happy to be playing something like FL.
Now, the last two years, the standards have gone up. Modellers have matured and they can get into the Freelancer design mentality easier. Leaving all these old-school models without remaking them, only break the immersion for me, when I see some tiny jet-planes in space.
The only example of a ship with extruded engines I can think is the Humpback. The Stinger's proportions are very odd, having no "body", it's just a cockpit on two long engines with some "cool" wings. I could imagine it landing and transforming into a mech.
Not to mention it's black and lacks a transparent cockpit canopy.