Traditional panniers for animal transport are typically made of canvas, leather, or wicker. Modern panniers may be rectangular boxes of hard-sided plastic. Panniers are loaded in such a manner as to distribute weight evenly on either side of the animal. For horse packing, and when carrying particularly heavy loads on other animals they are supported by a pack saddle to distribute weight more evenly across the back of the animal. In some cases, additional items are placed on the back of the animal, between the panniers.
Tourists riding in panniers in France, 1833
Pack horse with soft-sided panniers
Panniers on a llama used to transport waste in a U.S. national park, 2005
Modern waterproof bicycle touring panniers, Berlin, 2009
There are many styles of bicycle panniers. Touring panniers come in both rear and front styles, usually sold in pairs, intended to hold enough equipment for self-sustained tours over days or weeks. Commuters who bicycle have pannier options designed to hold laptop computers, files and folders, changes of clothes or shoes and lunches. Since the movement against disposable shopping bags emerged, many panniers are made easily detachable from the bike, to allow using them for shopping bags. Some cyclists create makeshift pannier bags out of grocery bags, grocery baskets, garment-bags, convertible backpacks, and various multi-purpose bags as alternatives to purchasing a commercial pannier.
The first panniers designed specifically for bicycles were patented by John B. Wood of Camden, NJ, in 1884. The modern bicycle pannier was invented by Hartley Alley (1919-2001) of Boulder, CO, in 1971. Alley also designed a handlebar bag and other bicycle luggage that he manufactured and sold under the Touring Cyclist brand in the 1970s until his retirement in 1984.
Bicycle panniers are usually made of nylon or other synthetic fabric. As bicycles are often ridden in the rain, many panniers are built to be water-repellent or waterproof by themselves. Others include built-in rain-covers, or rain-covers are offered as accessories. The shape of the pannier may be enforced by a frame or stiffening panel made of plastic or metal to help keep it in place and prevent it from contacting a wheel.
Panniers are usually built to attach to a rear rack or front rack already fitted to the bicycle. Removable panniers hook onto the top edge of the rack and are often held in place by a latch or elastic mechanism.
Motorcycle panniers are generally hard box containers with lids, made of metal or hard plastic. The panniers may be permanently fixed to the motorcycle or may be removable. Soft cases may be leather or fabric usually without permanent mountings and are often called saddlebags or 'throwovers'.
External cargo compartments on aircraft are also called panniers. They are similar to drop tanks, although they carry cargo rather than fuel and are usually not jettisonable. Aircraft panniers are usually mounted singly under the aircraft's belly along its centerline. Streamlining is an important consideration in the design of aircraft panniers.