Use of English PRO

Long after a flight is sold (0) OUT, airlines continue to oversell tickets. At departure time, if the flight is overbooked and more passengers arrive with confirmed reservations than the airlines (1) ............ seats, the gate attendants will ask passengers to voluntarily (2) ............ up their seats for some form of compensation — (3) ............ cash or a free ticket for use on the same carrier at a later date. The carrier then puts the volunteers (4) ............ the next available flight they have going to that destination. (5) ............ the time, these giveaways probably appear very attractive. However, this type of 'bumping' (6) ............ not regulated and these volunteer bonuses (7) ............ to be negotiable and dependent (8) ............ the gate attendants trying to get the flight off the ground.