What is the flight plan extension for the 737NGX? Is it .rte .pln or .sfp?As I understand it, the flight plans are located in PMDG/FLIGHTPLANS/NGX.I have all 3 flight plan extensions. But when I place either of them in the folder, I get INVALID ENTRY in the FMC..Thanks!Mark

I don't think you can load default FSX plans into the FMC. They need to be in PMDG format. You can create and save plans as 'Co routes' from the CDU.

From my experience, they can also just be in the PMDG/FLIGHTPLANS entry. Haven't had to go into PMDG/FLIGHTPLANS/NGX folder, recently. Initially, that's where I put them, but I tried just putting them in the PMDG/FLIGHTPLANS folder, and I haven't had any problems.