register with the embassy. so it is a voluntary -- it is a voluntary thing. >> reporter: as he rushes to meet an august 31st deadline, president biden has privately told top aids he doesn't want any empty seats on any flights leaving kabul. >> we intend to maximize each plane's capacity. >> we're not holding up a plane just to feel it with americans and then saying enough. >> reporter: taliban check points have made the journey to the kabul international airport a perilous one. the u.s. is relying on commanders of the taliban to let people fleeing the taliban access the airport. >> we have seen reports of the taliban harassing and physically so some afghans that were trying to move to the airport. >> reporter: biden was briefed on the latest by his top advisers in the situation room today. yesterday he told abc news he doesn't recall if some of those same advisers urged him to keep a military presence in