PORT-AU-PRINCE, Haiti — The aid flooding into Haiti by plane and boat is not reaching earthquake victims quickly enough to stem growing unrest because of transportation bottlenecks and isolated violence.

Many foreign aid workers and Haitians said ample donations are arriving, but express frustration at the slow pace of distribution of food and medicine from Port-au-Prince's port, airport and a warehouse in its sprawling Cite-Soleil slum.

"There's no top-down leadership. ... And since the Haitian government took control of our supplies, we have to wait for things even though they're stacked up in the warehouse," said Dr. Rob Maddox of Start, La., tending to dozens of patients in the capital's general hospital. "The situation is just madness."

U.S. air traffic controllers have lined up an astonishing 2,550 incoming flights through March 1, but some 25 flights a day aren't taking their slots. Communication breakdowns between Haitians and their foreign counterparts are endemic.

"Aid is bottlenecking at the Port-au-Prince airport. It's not getting into the field," said Mike O'Keefe, who runs Banyan Air Service in Fort Lauderdale.

Boxes of supplies are stacked to the ceiling in the dimly lit warehouse of the capital's hospital. In another storage area, medicine, bandages and other key supplies pile up on tables — watched over by a Haitian health worker who scrawls in a notebook, ticking off everything that comes in and out. Doctors say since locals took over the supply room, crucial time to save lives has been lost filling out unnecessary forms.

Donors talk about key logistical challenges: Grappling with a barely functioning government, the backlog of flights, a damaged and small port, clogged overland routes from outlying airports and the Dominican Republic, and security.

Aid agencies say food and water deliveries have about doubled in the past 10 days, but some relief workers are frustrated at how long it takes to move other supplies out of the U.N.'s warehouses.

U.N. officials said Tuesday more than 100 ships are en route to Haiti, but the capital's port has limited capacity.