FlightGear

FlightGear is a open-source flight sim(FREE!), It is pretty good, unlike Combat Simulators, FlightGear is like FS2004 or FSX, etc. You can fly from anywhere in the world to anywhere(have to have fuel of course 🙂 ). It is a simulator(not a game, has aerodymanics).

AIRCRAFT:
The Base FlightGear comes with many aircraft, but you can download more and more for free! 😀 ! Many of the aircraft won't work out for my FlightGear because it is a old version......

SCENERY:
The base flightgear only sets you to San Francisco Area, but you can download a part of scenery you want, or the entire world! I say the Graphics is like between FS2000 to FS2004(v9.10), the new version(didn't work out for me, ahh!!!!!!) is like FS2004 or better(NOT ON FRAME RATES!)
FlightGear(v9.10)'s airport is not detailed, no buildings sometimes, but in some places(like St Maarten, San Juan, Baltimore), it is detailed(FRAME RATES WILL BE BAD)

FRAME RATES:
WARNING: Try not to fly on full screen mode, it works really bad on my computer, green and really bad(Really Bad) frame rates.
But not on full screen mode, you can enjoy it! But the frame rates may still be bad in detailed places like St Maarten.

Go ahead and download it if you want, right here: https://flyawaysimulation.com/downloads/files/1366/flightgear-for-windows/

INSTALLING NEW(addon) PLANES(optional):
u install planes by putting the plane's folder to FlightGear\Data\Aircraft\, It's almost exactly the same as FSX or 2004! BE WARNED THAT ONLY A FEW PLANES AT flightgear.org WORKS, Here are the ones that worked:

Beech 99 i think

A4

Beechcraft Starship

and few more, one millitary aircraft seem to......NEVER DOWNLOAD THAT ONE

INSTALLING NEW SCENERY(optional):
go to flightgear.org and under downloads click download more scenery, find world scenery map and click the chunk of area you want to download and save the file(I can't open), Then after saving, go to your computer's start menu and find flightgear and click Install and Uninstall scenery, find the place you saved that file, and select it and install it, then after installing finished go start flightgear and on the airports list click reload airports, after reloading new airports should come into the list!

Why the new version 1.9.1 didn't work out for me?
Cause the frame rates are like 0fps, AHhhhhhhh!!!!!!!!!!!!!!
And it ruins my old flightgear I have to uninstall my old flightgear and reinstall it!