It has the earmarks of it, I think. She could have been told beforehand, but maybe it was better to wait until boarding time to see who all the hidden players were. Going by Sara Carter's tweet that Pelosi was on the tarmac that it was stopped at boarding time. It would be like a police sting where the target has to actually be in the process of a crime before they nail him.
Another thing was Schiff's first response about POTUS stopping a congressional oversight mission (assuming military). Schiff has been yapping all the time about putting together a commission and has been hiring wonks to investigate Trump's businesses. If Schiff's first tweet had been about Trump trying to obstruct them finding out stuff about his international businesses it would have had a lot more bite. Tells me Schiff was off his game and was just trying to throw shit at the wall in panic mode.