How about:
one hostage freed -> no aerial bombing for 24 hours
There also should be an incentive to release more than one a day. Perhaps a 12-hour bonus for every one after the first on any day.
Release 4 hostages on Tuesday = 4 days + 36 hours no aerial bombing
Under my proposal, most Gazans would have a personal incentive to free hostages and Israel might be able to wait patiently. Also, Israel would not have to release terrorists so they can get a chance to kill again.
one hostage freed -> no aerial bombing for 24 hours
What happens after all the hostages are freed?