Hi Fernando,
Are all of your airplanes missing, or is it just the default ones, or just extra ones you have downloaded? Can you confirm that there are folders with .acf files in them in your X-Plane 10 -> Aircraft folder? Please start X-Plane and take a screen shot of the aircraft screen with no folders, then quit. Please upload that screen shot and the log.txt from the X-Plane 10 folder to a comment on this thread.