Press poor
Sorry but I felt obliged to share this from The London Evening Standard which has a two page picture spread with an inaccurate report (and transcript) of the AF incident under the headline "Damn it, we're going to crash, this can't be happening." to draw attention.
"There are striking parallels between the two incidents. The Malaysia Airlines flight was at an altitude of 35,000 feet, while the Air France Airbus A330-203 was 3,000 higher at 38,000ft, both planes were state of the art and neither sent a distress signal."
This serves to remind, as I am sure all appreciate, that the media is increasingly desperate to fill space with anything vaguely related to keep the public interest alive, however spurious. The blondes in cockpit is arguably in the same league. It is of course possible, as it always was, that the crew invited someone into the cockpit, but there is no evidence to suggest they did on this flight or that this had any relevance. Hijack was and is a credible possibility. The blonde in cockpit story doesn't sensibly change that either way, unless someone shows a passenger manifest with a stunning blonde model with credible terrorist connections.
I would focus speculation on what might have caused what appears to be a sudden re-route, descent, and loss of multiple comms systems but I sincerely doubt now that we will get any closer at all to picking between hijack and a substantial event, deliberate or structural, until the aircraft is found regardless of how much vaguely related spice the media dredges up before then.