(Rob from SkyDemon)
Yup, the 30 day free trial has very few limitations to it, but the key one to note is that nav mode works for 30 minutes and then stops for at least 10. We do pop up a little message confirming this fact at the point the pilot presses "Go Flying" in addition to spelling it out on the website.
The simulator function is time-unlimited though, and that is probably more suited to giving a feel for how the software will behave inflight; the aircraft symbol will attempt to take off and follow the planned route, generating all the warnings you would expect. You can drag the aircraft around with your finger to prompt warnings and get an idea how they all work, and even "Spawn Aircraft" at specific points so as to see how the traffic warnings will appear without needing to get into a collision situation yourself
SkyDemon Light, by comparison, has no nav functions inherent and quite a lot of the regular planning functions from our "full fat" product are simply absent - its only really a very basic planning and NOTAM visualisation tool; hard to beat on price though
