The site/message is good, but I'm not sure I would ever promote any in-flight entertainment system as a great example of a development framework in action. Almost every one I've used has been among the slowest, clunkiest, crashiest, most unresponsive, poorly designed "modern" UIs I've ever used.
In order to avoid being entirely critical, however, Qt does serve a role that few other dev platforms do, and although I suspect there are better alternatives, I'm glad that there is still strong support for it!
I had the chance to fly with Delta this summer, the electronics had been updated in my flight, and the UI was great and felt "responsive" in a certain way, let's say 5 times better than before.
The problem you have there is not only one of outdated hardware, but also an issue of software certification and other software red-tape in that industry. A friend of mine was working on one of those systems in the past (IIRC, they used Qt) and it takes a long time for that stuff to get released...
In order to avoid being entirely critical, however, Qt does serve a role that few other dev platforms do, and although I suspect there are better alternatives, I'm glad that there is still strong support for it!