"Has Hamas allowed in the aid carried by the flotilla yet?
Why the delay?"

June 30th

"One month after Israeli commandos killed nine Turks in a raid on a flotilla trying to break the Gaza blockade, the ships' cargo of aid has begun to arrive here by land, starting Wednesday with 82 second-hand battery-powered scooters for the handicapped.

The cargo has been sitting in Israel for weeks while the Hamas authorities, the Israeli military and international aid agencies negotiated its fate.
Israel wanted to send in only materials that it was sure could not be used for weapons by Hamas.
It also did not want the sponsor of the flotilla, a Turkish Islamic charity known by the initials I.H.H., to distribute the goods
because of its close ties to Hamas

In the end, the United Nations agreed to distribute the goods.

A convoy of 128 trucks carried the cargo into Gaza from Israel as the American Middle East envoy, George J. Mitchell, watched from the Israeli side. He expressed approval at Israel's agreement, in the wake of the flotilla disaster, to ease its blockade somewhat, though the movement of goods and people out of Gaza remains largely blocked.

Mr. Daher, of the World Health Organization, told Israel he would NOT accept the scooters without their batteries and chargers, something Israeli officials considered withholding out of fear they would be diverted to militant use."

From The New York Times

Hamas had said that it would accept the cargo in its entirety including the batteries required by the scooters and the much needed cement