The majority of my time working at Thales Avionics has been developing Inflight Entertainment GUIs for different airlines using Qt/QML. Though I was hired to do Android development, the company made the switch from Android to Qt/QML for new GUI projects shortly after I was hired. Rather than continue to work on legacy Android projects, I elected to learn Qt/QML so that I could work on new development (though I have continued to work on some Android projects when needed).
The UI layer of the Inflight Entertainment system is split between a UX framework done in Qt/C++, and the top-most layer done in QML/Javascript. The UX framework layer provides an interface for the GUI layer to communicate with the lower layers using APIs. I mostly work on the QML/javascript side but also occasionally implement new APIs in the Qt/C++ layer as needed. There is also a lower level Java-based UX framework that I work on as well.
I have worked on many customer GUIs including JetBlue, American Airlines, Air Canada, Saudia Airlines, Singapore Airlines, and China Southern Airlines, and was the project leader for the American Airlines GUI. Some of the projects are using very old hardware with storage/CPU limitations, so while we try to deliver modern looking GUIs with smooth animations we also have to be conscious of how to do this in the most efficient way possible.
The design mockups for these GUIs are provided by a 3rd party design agency. While developing the GUIs, I try to find ways to improve or enhance the designs wherever possible and work closely with the product owner who takes suggestions and ideas back to the airline customer. For example, I helped to add a fun balloon animation into the JetBlue GUI for passengers traveling on their birthday (see video screenshot below).