Our of curiosity, would it be technically feasible to load a flight plan directly into MSFS (or FSX) using simconnect, without having to save it into a file and then load that file in the sim?

Yep. Doable (SimConnect_FlightPlanLoad) via a temporary file. Already on the list https://github.com/albar965/littlenavmap/issues/35

But don't ask when.🙂

Alex

Oh, nice! Thanks for the reply. I may hack together something for this in the meantime. With MSFS load times being so slow, it's a drag to have to exit and re-enter in order to change the flight plan.