As pointed out in an interesting Gamers With Jobs podcast last week, flight sims can be similar to single player Minecraft, in that part of the 'fun' is the simple zen-like act of wandering around viewing the scenery and doing pretty simple stuff; in this case, waggling the joystick.
But there's no denying that much of the attraction when it comes to sims is learning complex systems and pretending to be a real pilot delivering sort-of-justice to the unfree world, or 20mm lead to Nazis. It's like picking up a virtual rifle and shooting, only it involves a bit more effort and dedication... and a lot more time.
Unfortunately being a pilot is mostly boredom followed by short periods of hyperactivity. And when it comes to translating that reality into an involving game, most sims have struggled (IMO).
Wings of Prey (WWII) is as close as any sim's got recently, and many 'serious' sim pilots look down their noses at it. But it has a decent balance between simplicity and hardcore reality, especially when you can get it regularly for about a tenner on Steam. There's a demo which is worth exploring.
IL2 1946 is also £10 on Steam these days (much less on DVD, I see), but although it's a bargain, a beginner might struggle to have fun unless they were bitten by the "ooh, another aircraft to explore!" bug, or the "oh look, I crashed again!" bug.
For modern stuff a search shows you can pick up the original 'Lock On' for about the price of a sandwich. Eagle Dynamics make sims which are impressive, but Russians are allergic to fun, so you have to buy into the stuff I mentioned above above to get much satisfaction from it. I must admit I spent most of my LOMAC life just flying around avoiding action at high speed.
Of course without a joystick sims can be a bit of a challenge, and the fun of simply flying a believable aircraft will be lost. That adds to the cost of exploring this genre, and I'm not sure an analogue controller (if available) is a decent alternative unless you have very fine control in your fingers.
So, er... flight sims. Yea, they're a bit weird. But probably no more weird than playing Left4Dead at 1am with the lights out.
Andrew McP