I made a little more detailed comment in the thread that contains the audio clip of this:http://www.liveatc.net/forum/viewtopic.php?p=3211#3211
I played the radar depiction a number of times, and it was always the same.
I played both the audio clip and the radar depiction for my wife (a controller, who has worked at BOS tower, coincidentally), and she advises that everything was clean. Apparently, the philosophy at BOS is to expidite traffic, period, even if there are only two aircraft in the airspace. As long as the Lear had AAL in sight, and the controller had been told that, there was no violation of any sort. My wife suspects that the Lear pilot said he passed 1000 feet below AAL "for the tape", not because he was worried that *he* was in the wrong, but because he wasn't sure he hadn't gotten the controller in trouble.
Since she's my wife, it's my prerogative to disagree with her (as long as she doesn't find out).
Personally, I still don't like the way the situation played out. Just because it was all legal by the book, doesn't mean it was done in the best judgement. The Lear had been given his turn to 270. He could have expedited his turn, or maintained 5000, or both, passing well below and behind AAL.
I can't imagine that the pilot was the only one on board the American to be looking out the window. If the two aircraft passed close enough to bother the AAL captain, imagine how worried his passengers might have been. The behavior of aircraft in general these days draws more than its fair share of public suspicion, from both those on the ground and in the cabins. Why add to the the tension that already exists?