Simis' "AV-8B Harrier Assault" (later upgraded to "SVGA Harrier", the first 640x480 PC flight sim) flew rings around "Jump Jet", IMO. Jump Jet may have had gouraud shading, but it was simply outdone in every other department by itss rival. To this day SVGA Harrier is my favourite flight sim of all time. (I can't get it running on a modern PC, though
Super-smooth hi-res graphics (with a gorgeous fading-colour/haze effect on the terrain as it got more distant), great flight modelling (for the time), and a truly dynamic campaign in which you controlled air, sea, and land forces, and could plan ahead for coordinated strikes, add new missions at will, and fly (or not) any harrier mission personally.
Harrier Assault rocked. And ever since the cancellation of Flying Nightmares 2, I've been pining for a modern Harrier sim! So my very best wishes to everyone at Thunderworks -- may the project go smoothly, and be successful!!!