I’m speculating that real aliens would somehow cloak their ship so our technology couldn’t see them. The radar jamming is too close to our technology to be, in my opinion, an interplanetary alien.
I so very much agree.
As you didn't mention it:
- Clarke's Third Law: Any sufficiently advanced technology is indistinguishable from magic.
- Profiles of the Future (revised edition, 1973) Arthur C. Clarke