After initial misgivings, the U.S. Air Force went ahead and dropped relief supplies, by parachute, in Haiti. At first, the air force was reluctant to do so, because the areas to receive the supplies seemed to be in disorder. It was feared that most of the supplies would be stolen by gangs, and put up for sale. But on January 18, drops began (15,000 liters of waters and 15,000 MREs) to areas where U.S. troops were on the ground, and able to supervise distribution.
The U.S. frequently uses food air drops in emergency situations. Two years ago, American air transports saved thousands of lives in Afghanistan, during one of the coldest Winters in living memory. Over a thousand people died from the severe cold. Heavy snow cut off many villages. The air force dropped about 175 tons of emergency supplies to isolated villages in February, in addition to 325 tons dropped to U.S. and NATO military units. The air drops were up 40 percent from January, mainly because of the need to get emergency food, fuel and other supplies to desperate villagers up in the mountains. Helicopters are often used for this, but some villages are in locations where it's simply easier to do an air drop, or because all the helicopters were busy with a combat mission, or because the drop zone was too high up for a helicopter. There was no problem with disorder, or the supplies being stolen, as each of the villages had their own leadership. Besides, no one was going far in this weather.
The U.S. Army provides the riggers, who put the supplies on pallets, then add the parachutes. The pallets hold up to a ton, or as little as a few hundred pounds. C-130s drop most of the pallets. Sometimes GPS guided parachute systems are used, especially when the drop has to be at night, in hostile territory. The "humanitarian drops" are usually called in by civil affairs or Special Forces troops who find out about particularly desperate situations.
The MRE (Meals Ready to Eat, in a pouch) are frequently used as emergency rations. The MRE has evolved from its initial introduction in 1983 (12 separate entrees) to today (24 menu entrees). The MREs change from year to year, and new entrees are added in place of others. The U.S. military has generally switched out entrees each year (apparently the notion that such a deal is a zero-sum game seems to persist, as opposed to just adding new ones). This constant evolution has done much to diminish the bad reputations MREs had early on. Back then, the MRE (officially, "Meals, Ready to Eat") was often called "Meals Rejected by Everyone".
The United States also has other rations, including variants for cold weather (which has a higher calorie count than the regular MRE 1540 per meal compared to 1250 for an MRE), and a kosher/halal variant for Jewish and Moslem soldiers (both religions, for instance, forbid the consumption of pork). Vegetarian entrees are provided, as well. The United States also has developed the Humanitarian Daily Ration (HDR), which has three meals and is based on vegetarian entrees to provide a low chance of offending cultural sensibilities. Many of these HDRs were dropped over Afghanistan in late 2001. Several hundred thousand HDRs are stockpiled for disaster relief, and production can be ramped up quickly. MREs and HDRs are particularly attractive because they provide uncontaminated food that does not require refrigeration, in a compact package. The UN, and many other food aid organizations, use the HDR for situations like Haiti.