As such, new physics code and an engine were developed, the former because the programmer of Flight Unlimited's computational fluid dynamics system, Seamus Blackley, had left the company.

[1][2] Players may control the Piper PA-28R-200, de Havilland Canada DHC-2 Beaver, Beechcraft Baron 58, North American P-51D Mustang or Cessna 172.

[4] Adventures are pre-built missions, with objectives such as landing on an aircraft carrier, helping a prisoner to escape from Alcatraz Island or dropping turkeys into Candlestick Park.

[2][12] The team eschewed the aerobatics focus of their previous game in favor of general civilian aviation,[2] in order to compete with the Microsoft Flight Simulator series.

[2] Programmer Jim Berry, who had previously worked on simulators such as Falcon 4.0, wrote new physics code based on force vector calculations to replace the CFDs system.

[2][6] To gather data for the new physics, Hantzopoulos and Berry flew in real-world planes with designer Ed Tatro and aerobatic pilot Michael Goulian.

[2] Flight Unlimited uses distance fog to limit visible terrain, but this causes pop-in issues that the team sought to avoid in the sequel.

[7][15] Instead of removing textures that exceed the draw distance, the new engine uses mipmapping to lower the polygon count of distant terrain.

[17] Radio communications between ATCs, AI planes and the player occur in real-time: a "sophisticated audio splicing system" gathers pre-recorded voice fragments into contextually appropriate sentences.

[2] To generate the terrain, the team combined digital elevation maps with satellite imagery rendered at four square meters per pixel.

[23] Looking Glass's Tim Stellmach and Paul Neurath described the merger as amicable, and the former noted that "through the whole deal everyone was really psyched about both The Dark Project and Flight Unlimited II".

[21][22] In September, Eidos took over publishing duties on Flight Unlimited II, as a result of Looking Glass's new business model with Intermetrics.

Poole summarized, "Flight Unlimited II is so impressive that to even whine about little details shows a shortsightedness that's all too common amongst us gamers.

"[1] John Nolan of Computer Games Magazine found that the new flight physics were "more than adequate for the task at hand", despite certain "questionable areas".

[5] Similarly, Edge praised the believable and highly detailed environment, noting that Looking Glass Studios managed to cleverly soften the contrast between photo-captured textures and polygon objects "using haze as a real effect rather than a distance-clipping cheat".

He noted that the graphics, while good from a distance, became "disappointingly bland" up close; and he found the game to be limited compared to Microsoft Flight Simulator '98.

The editors called Flight Unlimited II "the first aviation sim to truly capture the environment of real civilian flying".

[31][32] Flight Unlimited III lead designer Peter James later wrote that his project's development was troubled, in part because of a lack of interest from company management.