Sounds like justification for a false flag operation by the US government. How would they transport these massive things and launch them on a different continent? That, or the US is trying to justify that this illegal war is on their doorstep and need to expand their terror.
The drones Iran are using are actually relatively small, you can fit 5 of them into a medium sized truck and they can launch in-situ, which is how they've been using them in ground operations. Doesn't seem that much of a stretch to put a bunch of them into shipping containers.
"Reichstag fire" attempts are definitively a legitimate concern. But as Ukraine has demonstrated, all you need to get a drone army deep into a country attacking you is a regular shipping container.