Or, as I've posted elsewhere, don't even bother with a physical flight. In the US, where two people are required on the flight deck, all flight personnel are automatically eligible to be Federal Flight Deck Officers, meaning that after taking some amount of training they can carry firearms on the plane with them, and other flight officers/staff are prohibited from asking or knowing that they're carrying weapons. If pilots want to crash a plane, it's not going to be difficult for them to succeed.

Or just pulling out a gun and shooting the other person in the cockpit, locking the door, and doing the same thing that happened here.
All flight crew members are automatically Federal Flight Deck Officers and are allowed to carry guns on the plane, and other flight officers are prohibited from knowing that their coworkers may be carrying guns.

In the case of pilots, there is a legal requirement for the pilot to get checked out medically on a regular basis. For US airline pilots the maximum time between medical checkouts is six months.

However, that statement is completely orthogonal to the other problem, which is that many people who could pass a psychiatric assessment kill themselves or others, and a large number of people who would come out of a psychiatric assessment with a big thick file of observed problems are perfectly reliable individuals in their daily lives and would likely be completely competent pilots.

Oh I think there are definitely symptoms of homeopathy...

So let's treat it as a reciprocal. The efficacy of homeopathy is 1/amount used, so as the amount used goes to zero, the efficacy goes to infinity, and... beyond!
(Well, okay, for 'beyond' you'd have to use a negative amount, but that's what happens when you get someone else to use yours, I guess?)

One thing to consider is total cost of ownership, and over the lifetime of an LED, you would have bought somewhere between 30 and 100 incandescent bulbs.
Another thing to consider is that the one LED will use about 1/8 the power of those incandescents, so unless your power is free, you're now looking at 240-1000x the total operating cost for incandescents compared to LED's.
My next-door neighbor has very little money, so back in 2009 she bought a big SUV because it was $1200, compared to $3000 for a subcompact... and then couldn't afford the gas to get to work. People are really lousy at looking at anything other than the initial purchase price.

A third thing to consider is that as fewer people buy incandescents, the cost of maintaining tungsten-drawing machinery and other lightbulb-specific manufacturing equipment is going to rise. Vacuum tubes are hard to make well, and while we have a century of experience in doing so, silicon is dirt cheap and getting cheaper.

If they think Homeopathy doesn't work, they're just not using enough.

Or, wait, sorry, they're using too much.

The less homeopathy you use, the stronger it is.

The logical conclusion is that if you use none at all, you'll see the greatest improvement, especially financially.

Nobody else knew it existed, which meant there wasn't a crapflood of angry reviews everywhere. I used it to put hours of operation notes on a bunch of local businesses that didn't list them, and in the case of one oddly-set-up webpage, instructions on how to get it to work. (Trying to get samples from a company that for whatever reason ships to just about every country in the world save the US, and if you email them about it they say oh yeah register as canadian and give a us address, rather than registering with a us address, submitting the sample request, and simply never getting any sort of response at all.)
Sidewiki would have become useless if it had been popular, but as an almost unknown service, it was extremely useful.

Geeks make robots. Nerds role-play robots. Dorks dance like robots.

It's entirely possible that plane could be fixed. I've seen much worse aircraft restored, and the PT22 is a particularly simple aircraft. It's an interesting choice for a very, very rich high-time pilot to be flying, in fact: originally without any electrical system at all, implying hand-propping to start it, mechanical flaps, gravity fuel system. Main wingspar made of spruce. It's like someone who can afford a Ferrari choosing to drive a Nash.

On the other hand, there is a case to be made for an aim-for-the-stars strategy. If you can build a turbine blade you can build anything. I would have thought compressor blades would be a much more likely candidate, but if they can get this to work, more power to them. And maybe 3d printing will give them options they would not otherwise have: internal bleed air cooling channels that follow the leading edge along its curvature, for instance. It's possible that given completely different design and manufacturing capabilities, they'll be able to make something that can do the same job with different tradeoffs.

As Martin Niemoller said, in a different context:
"First they came for the Socialists, and I did not speak out—
Because I was not a Socialist.
Then they came for the Trade Unionists, and I did not speak out—
Because I was not a Trade Unionist."
and so forth. If they first kill off the homeless, then they kill off the very poor, then they kill off the illegal immigrants, they never have to pacify the majority. They just have to keep them scared enough to not protest.

By the way, Neil Postman wrote an interesting book called "Amusing Ourselves To Death", where he compared the futures predicted by Brave New World and 1984 and talked about why he thought we were heading towards Brave New World. Some of his information is pretty dated -- he totally didn't expect the universal surveillance state we seem to be entering into -- but it's still an excellent exploration of what you're suggesting.

If it costs $1B to get a drug through the FDA approval process, and your prize is $2B, you will only play the game if you think you'll get your first or possibly second try through the approval process. If you have to start half a dozen and have them fail at various points through the approval process, you've already spent the potential prize money without winning it.

We might need to look at how safe drugs have to be before they can be FDA-certified. I've harped on this before but I know people who thought Vioxx was a lifesaver in treating their arthritis, and experienced a very significant change in health and happiness when it was taken off the market because of the harm it did to other people. If we insist on drugs that have statistically significant positive effects, with infinitesimal negative effects, we may run out of options and end up dying the way people did in the middle ages, while the drugs we need sit on a shelf somewhere, waiting for a different regulatory environment.

Don't be. We may breed triclosan-resistant bacteria by using antibacterial soap, but that doesn't mean we're breeding carbapenem-resistant bacteria -- the C in CRE -- by using triclosan. There is very little evidence that developed resistance to one type of antibiotic increases resistance to another completely unrelated antibiotic. Triclosan inhibits fatty acid synthesis, carbapenem inhibits synthesis of the peptidoglycans used in bacterial cell walls.

Mostly through concentration: making sure there are 100x or more antibodies against HIV present than the cells HIV is targeting.
But it's also helped by binding affinity. When a receptor and a substrate bind, it's generally reversible -- they can join or separate, and there is a measurable equilibrium between the bound and unbound states, which is a function of concentration of both receptor and substrate, and a constant that reflects how well they actually stick together. Generally, antibodies are _vastly_ better at sticking to things because they're designed to be. (Okay, the 'designed to be' is not actually true but for the purposes of this, it's an okay approximation) So if your antibody/HIV binding affinity is 100x better than the HIV/cell binding affinity, and you have 100x more antibodies than target cells, the number of viral/cell bindings is going to be much lower than the number of antibody/viral bindings.

This is interesting, because my diet, such as it is, is almost exactly the opposite. I eat just over 1 gram per kilogram of body weight of protein, and about the same amount of fat, and then fill in the rest with carbs. But I'm a bike racer, so in the winter that may be 3000 calories of 70% carbs, where in mid-summer that sometimes stretches to 6500 calories a day, close to 85% carbs -- and I can't manage to get through the summer without losing 10 kilos, at which point I'm below 6% body fat and health issues start showing up and I have to start adding some fats.
Metabolism is weird.
One of my microbiology professors used to say that he felt humans were giant life support units for mobile ecosystems. He felt that much of what we think and feel is actually manipulated by our bacteria to benefit them and deter invasion from other bacteria.