I began this post about an hour ago. Then I came across something strange. I believe the AP story (linked below) as presented on the WWW may have been edited to remove any mention of "jamming" radio signals around Tehran.

When I first read the AP story this was mentioned, but, as everyone knows, every civilian flight bears a "transponder" -- a radio device that constantly emits a signal identifying the plane and the flight it is on.

I went to cite this passage from the AP story, and it is poof gone! Here is how I began this first version of this post, and you can see where I broke off typing to retrieve the AP story language mentioning jamming of radio signals:

Although Drudge has notoriously taken a hard turn left-ward, he gets props and a h/t for linking an AP article on the debacle of the Iranian shoot-down of a civilian flight out of Tehran's airport. AP, in its turn seems also to have done the right thing, and written a piece of informed news reporting, rather than the partisan cant they seem unable to avoid these days. The article brings out this fascinating fact:

The question of the transponder has not however been lost. From the NY Times:

The Tor software relied on radar and visual identification of a plane as well as the identification signals from the transponder, John Cox, an accident investigator and former pilot who is the chief executive of Safety Operating Systems, said. If the identification is incorrect or absent from the plane, Mr. Cox said, the system "will declare it a threat."

"Tor" is the code-name for the Iranian anti-aircraft system that was evidently in play. I suggest we all stay tuned for more on this question of transponders and "jamming."

Found this tonight.

Still going through the comments but transponders do not appear to figure prominently in the speculation.