In Flight Plan, why did the hospital say the girl was dead?

I can't remember who in the movie said that the girl had died at the hospital, it may have been one of the hijackers? That would make sense. But if not, how did they get the hospital to say the girl was dead?

Yes, someone did say the girl was dead.
Someone said they contacted the hospital and she had been taken to the same hospital her dad had been taken to, and died.

That was also a big part of what the therapist was talking to Kyle about! She was talking about how it's easier just to deny things like this, but eventually you have to come to terms with what happened so you can move forward, etc.

The security guy and the stewardess were in on it together and made it look like that was an authentic message when in fact it was not. It was done on the phone and not the radio so it did not go through the cockpit.

i dont think that ever happened...

nobody said the girl was dead. they just said they didn't see her get on the plane.