I installed a few aircraft from Simairline.net and installed them in the airplanes section under simobject. The airplanes wont show up when i start FSX. Where are the aircraft located or did I install something wrong.
If it means anything the aircraft that were downloaded were:
Cathay Pacific 773
Air Canada 772/LR
Virgin Atlantic 744
your file path should be:
hard drive letter/microsoft games/flight simulator x/simobjects/airplanes
In their tutorial they use a POSKY as an example.
If you downloaded POSKYs according to your choice of airlines, it's likely that the 'ui_manufacturer=' has been given an exotic name such as POSKY, Project Opensky or Opensky... It should really be Boeing or Airbus respectively because that's where you're going to look.
I suggest you read the tutorial again and pay particular attention to the section dealing with the 'aircraft.cfg file'.