Bigger isn't necessarily better, here. There's a term for "small jet turbine powered autonomous suicide drone" already - "cruise missile" - and it's something that the US military has put a lot of work into stopping.
Small drones aren't really part of the same threat profile, near as I can tell.
Cruise missiles generally have a diameter of around 70+ cm and a length of over 5 meters. They are also hideously expensive. These drones would have a diameter of around 15-25 cm, a length of a meter or two, a cost a hundredth of a cruise missile. Not comparable.
They're not bigger than a large camera drone, they're just much faster.
The US military has absolutely nothing that can stop a legion of a thousand or more "mini cruise missiles" such as these. Not a chance in hell.
Small drones aren't really part of the same threat profile, near as I can tell.