[tacticalogic]

As far as which nation, I figure any belligerent power with the technology to mass produce cars can do it. The only trick needed is once you have a design, to keep production secret. Using such an armada in a sneak attack would be devastating, likely defeating their hated enemy in a week.

I'd imagine building them cheaply is going to mean they're going to have limited speed and range. That means you have to launch and retrieve them fairly close to the intended target, without making yourself a target in the process. I'd also expect they wouldn't have any armor and limited if any defensive capability, so you don't need high tech fighters to shoot them down.

[yefragetuwrabrumuy]

With that many units, they are single use, no retrieval. Much like buzz bombs, except far more accurate.