Think we actually covered this one. It's still pretty bad, but not *quite* that bad. A decent proportion of large commercial aircraft have a three man crew rather than two, which reduces the odds. There is also a chance of a passenger being able to fly. Even people without flying experience have successfully landed a plane with radio help.
Now, could air traffic handle every such emergency all at once? God no. But they might be able to save a few of them.
The unattended house fires is an interesting point, and does raise some problems, particularly in tinder dry areas like CA. That said, fires from car wrecks are exceedingly rare these days.Some households are suddenly entirely empty (half of all single-resident households, a quarter of the two-resident, etc.). In a few of those households, someone just put something on to boil, or started some other similar process that needs supervision. Expect a large number of fires to start, within an hour after the Snap. Plus whatever happened from all of those crashing cars and airplanes.
There'll also be some additional deaths from other critical absences. In surgery and the surgeon vanishes? That's awkward. Fortunately, relatively few people will be in a critical surgery at any given time.
It could make for a really fascinating apocalypse story, though.
Everyone wants to feel like they are prepared for everything. In practice, very few are (un)fortunate enough to be. The advantage of prepping is largely that it gives you longer to adjust to the new normal. Having a convenient stockpile of necessaries would probably boost survival odds for almost any scenario.The human species would survive. There are a few people out there who are genuinely prepared to deal with cataclysm (hint: Almost none of the "preppers" are). Half of those people will stay undusted, and they'll rally a few other survivors. But it'd be very grim indeed.
Thor:Ragnarok indirectly answers that. Executioner notably uses a pair of AR-15s to good effect holding off Hela's horde. Now granted, these were just standard military folks, raised again by Hela, but bullets pretty clearly work on them, so it doesn't seem like their bodies are bulletproof.
Hela is definitely pretty far up there, yeah. She'd do good against Thanos, I think. Far better ranged options, and fast. Yeah, Thanos is strong, but she's also fairly tough, and has vastly more firepower and mobility than Thanos generally enjoys. Stones kind of alters this, of course, but Hela against Thanos without stones? I'd bank on her.And absolutely no one survived against Hela except Thor and Valkyrie, and they wouldn’t have survived much longer if they hadn’t run away and let Surtur’s giant sword do the talking. I’d say the differential between Hela and all other Asgardians (less only Odin) is orders of magnitude greater than the differences among the Asgardians. Like Thanos, she’s in a class of her own.
Hela vs. Thanos would make for a great What If, though doubt if we’ll ever see that. But if puny human Stark can punch his way to a little scratch on Thanos, Hela and her infinite edged weapons should be able to make a lot more progress.