In March 2024, Nitrome mentioned that they were not working on Flightless due to several things changing since when it was greenlit, most notably that the game was done in Flash when Nitrome had moved on to Unity and that several of the staff members on the project had left the company.
The biggest reason was security. With a huge part of the tech world running Flash, it became a massive target for hackers, forcing Adobe to release updates often to patch problems. It also offered poor performance, causing some users to see full CPU usage when viewing web pages with Flash content.
