You can mitigate the cost of an airplane if you know what you are doing, and you don't need to be earning 100,000+. Simple airplanes like cubs, super-cubs, 150s, tripacers, and others can be had for pretty cheap. Some can even use auto gas. In good condition they may be a little more pricy, but the maint and upkeep on a simple plane is pretty cheap. Find a way to store it. Find an A&P that lets you do your own annuals and then inspects the work (or just budget in the annual cost), be aware of the overhauls and ADs, and you can have something that's fun, relatively efficient, and doesn't cost a fortune. On the other hand, if you get a 172 with a bunch of radios, navs, coms, systems, etc, costs can spiral out of control real fast, and it depends on how you can hangar/take care of the plane. I helped a friend buy a 150 who wasn't earning anywhere near 100K, he enjoyed it a lot. I recommended (and he did) sell it when he moved to very high altitude in CO, but it just wasn't practical at that location due to performance. Still, it was practical for him for quite a while and you can usually turn around and sell it in the end, sometimes for a decent amount if you take care of it.