RealFlight will recognize the XBox controller as a "Gamepad" profile.
Now that I'm trying this again (hooked up an XBox Series X controller via USB), I'm pleasantly surprised how well the default mapping works.
Left stick = Throttle (up/down) / Rudder (left/right)
Right stick = Elevator (up/down) / Aileron (left/right)
X button = Flight Mode, toggles between flight mode 1 and 3 (RealFlight Channel 8)
Y button = Dual Rate, toggles between low and high rates (RealFlight Channel 5)
A button = Flaps, toggles flaps full up and full down (Real Flight Channel 6)
B button = Both Smoke (Real Flight Channel 7) and Throttle Hold (RealFlight Channel 9), which should make it either toggle landing gear up or down on a plane, or toggle Throttle Hold on/off on a heli
The D-Pad will move the cursor around the menus. In RF Evolution, D-Pad left will open up the ESC menus, just like pressing the Cancel button on the InterLink DX controller.
- Up = Move cursor up
- Down = Move cursor down
- Left = Back up/Cancel
- Right = Select
Menu button = Reset (put the aircraft back at the starting point)
The bumpers are assigned to RealFlight Channels 14 and 15, which don't have typical functions. You could remap those to something else. I'd probably set one of them to RealFlight Channel 12 to control Panic Mode or Reverse Thrust on the planes that support those features.
The triggers are not assigned to anything, as Windows treats them as proportional inputs like sticks rather than buttons.
The buttons in the middle of the sticks are not assigned to anything but could be.
So, absolutely, it does work!
The only part that's really strange as mentioned in other posts is that the throttle stick self-centers, so it will apply 50% throttle unless you're holding it in a different position. It's really not a big deal while you're flying. The aircraft wants to take off immediately when it appears on the screen, but it's easy enough to get your thumb on the left stick, pull it back, and then press the menu button on the controller to reset and start over. If you aren't holding that stick because you're working with menus or something else in RealFlight, the aircraft will take off again, but you can just ignore it.