In a pre-drone world you can get explosives, divide them into X equal sized packages, add a timer set to the same point in time to each, then travel around the country hiding them in high-traffic areas.

Yes, that approach is inferior to the drone version. You have to hide them inconspicuously, and a bomb sniffing dog could find them. But you can visit a lot of places in a single European country or US state within one day, and unless the country is already on high alert you can hide something for that time span in public. Yet this doesn't happen. Even regular bombings are rare.

The reasons are manifold: In most places getting explosives isn't actually all that easy (unless you go the homemade route) and is a good method to get attention from authorities. But another factor is that there just doesn't seem to be a large interest in doing that kind of complex attack unless there is already an ongoing civil war. Actual terrorism is fairly rare, and the terrorists tend to be not all that sophisticated.

Are these kinds of drone attacks a scary new possibility? Yes, absolutely! Are they likely to happen? Not really. We might see it as a method to assassinate officials (imagine staging drones at a place where you know the US President will hold a speech in a couple months), but I doubt it will play a major role against the general population

The drone scenario is very different, all you have to do is get close-ish to your target. This is very different than having a stick of c4 sit on your target for months. You have to get them to drone-range, say in the back of a lorry, on a roof somewhere, in a box. Then the programming and or AI can kick in and do the last mile for you, whenever you need. Case in point is the Ukrainian attack on the air fields, they parked a lorry nearby.

Attentive people would find the bombs. Especially if they're on alert, which everyone who knows about terrorism will be at least to some degree.

Back in the day, if you forgot a bag on a British bus the driver would get it and run after you, so that it wouldn't be a bomb issue taking the whole day.

Not much. Autonomous targeting and control are quite new and currently take a fair bit of knowledge and skill to get right, but I expect those barriers to lower dramatically in the coming years. There might be power issues with such a long delay, but I'm not sure. I think the main drawback once this tech gets slightly more widespread is that most people who want to terrorize cities don't want to wait a year or two to do it.

For long running conflicts (Israel vs Iran for example) I expect we'll see some fascinating and horrifying attacks in the near to medium term. Of course anti-drone tech is also evolving quickly and I expect that to continue so the shelf life of any specific attack will probably continue to be rather short.

It doesn't really take much knowledge to set up an autonomous drone mission. It's not DJI-levels of consumer friendliness, but I know multiple people that made and fly their own drones, and it's not something you can't do with a few YouTube tutorials.

They're battery operated, so I think there's a time limit of a few months. Then, you want to be very careful with the infrastructure you leave behind (little pop-open doors/roofs for them to fly out of) to avoid future investigation. You're going to need some practice, your first try will just go to shit perhaps. Opsec while you're setting all this up is still a big deal that amateurs will have trouble getting right. But none of these are particularly insurmountable. With the correct software and careful planning, this will succeed at its goals.

Things you can't help: they will discover the remains of the drones, and also their origin. This evidence will eventually lead back to you (unless you have the aid of a enemy nation-state). Not a big deal if you're dying in a suicide attack, but maybe you don't want the extended vacation in the CIA's worst black ops rendition site.

What you're missing is the will to go through with it. Even state actors would get spooked spending months or years setting this up. One slip-up and you're in prison for life. When your country's existence is at stake, the process is easier.

> What am I missing?

Battery degradation, a year or two's worth of leaves and debris accumulating on and around the drones, literally all of the elements affecting them, animals, etc.

If I've gone to the hassle of setting up a high tech bombing attack, wouldn't I have also gone to the trouble of putting the drone in a self-opening container?

This no longer sounds cheap or relatively straight forward, it sounds more like an engineering challenge the requires technical expertise and skill to pull off, as well as considerable amounts of money.

Everything mentioned affects the operation of a self-opening container as well.

A self-opening container has a much easier problem to solve than flight.

You can probably get unsuspecting couriers to deliver last mile. Build a drone dock with cutter to open top of boxes. Mail a weaponized drone to an address within range of target.