Bottom line up front
: this is an extremely
time-consuming achievement, and I'd recommend that you do this one last, after you've completed all the other ones. Every hour you spend on weekly activities, bush trips, etc. will count towards the 1,000 you need for Wing Commander. Ever since Asobo patched the clock change workaround (detailed in ToastBubbles' solution), the only way to complete Wing Commander is to fly, fly, and then keep flying some more. You'll of course get Pilot Program, Century Club, Journeyman, and probably Night Owl and possibly even Hydroplaning as you work through this.
It will take a minimum
of roughly 42 days to complete this achievement, and that's if you fly 24 hours a day without stopping. I used this solution to run extremely long-haul flights on my gaming PC while I played Yakuza games on my Xbox. :)Here's the technical details of the solution:
1. Start a flight in one of the propeller planes (I recommend the Cessna 208 B Grand Caravan) using a custom departure in the air around 30 degrees south latitude.
2. Once you're in control of your plane, gain altitude and then:
2a. enable autopilot (AP)
2b. select an altitude of 17,500 feet (using the knob)
2c. enable virtual speed mode (VS)
2d. set vertical speed to 500 (using the dial)
2e. enable heading mode (HDG), and then
2f. set the heading to 90 degrees.
[The locations of these buttons vary by aircraft but the majority of aircraft have these features (in the Cessna 208 B Grand Caravan which I recommend above, they're all in the master group above the GPS map in the middle of the console, just under the physical compass). Just make sure to choose an appropriate plane to match your chosen cruising altitude (not every plane can go as high as 17,500 feet).]
3. You will also need to make sure you don't run out of fuel. You can go into Options \ Assistance and enable Unlimited Fuel for this flight (you can do this from the main menu or pause during the flight). You can also refuel in mid-flight, but you'll need to bind a key sequence to do so--see https://www.fanbyte.com/guides/microsoft-flight-simulator-20...
for that process.
The reason for starting the flight around 30 degrees south latitude is that the vast majority of this latitude is ocean. You do have to contend with the mountain ranges on the western coast of South America, but if you set your altitude appropriately you'll pass well over them (they're roughly around 15-16,000 feet). By going due east (or west, a heading of 270 degrees), you also won't have to contend with temperature changes either.
I had previously recommended saving the flight as a .flt file in case the game crashed, but I noticed that the autopilot behaved ... strangely when I restored, so if the game crashes (as it still does), I'd recommend just starting a new flight.
You'll see your progress update in the Profile section of the game and the Xbox Live achievement trackers updates in real time.