There are very few items that cannot be shipped by air, but there are many restricted items that can be shipped if packed and documented as per IATA  regulations.

Restrictions on air cargo for items that may endanger the aircraft or passengers’ health or safety, or cause property damage, the main categories being:

Explosives: fireworks and firecrackers, detonating fuses, etc.;

Gases: such as compressed gas, dry ice, fire extinguisher, gas cartridge, inflated ball, respirator, explosive automotive airbag, aerosol, gas lighter, gas cylinder, and lamp bulb etc.;

Flammable liquid: e.g. paint, gasoline, alcohol, engine oil, camphor oil, engine starting fluid, turpentine, thinner, mucilage, perfume, insect sprays,  air freshener etc.

Flammable solid, pyrophoric substances, and substances that emit flammable gases in contact with water: e.g. activated carbon, titanium powder, copra, castor products, rubber debris, safety matches, dry white phosphorus , dry yellow phosphorus, magnesium powder, and solid gum, etc.

Toxic and infectious items: pesticides, lithium batteries

Corrosive items: e.g. batteries, alkaline battery electrolyte

Magnetic substances without degaussing packaging, magnetic steel and other strong magnetic products: e.g. currency detectors, speakers, magnets

Items dangerous to public health: e.g. corpses & bones (inc. incinerated), untanned hides, animal bones not processed with chemicals

Oxidizers, organic peroxides, radioactive materials & corrosive items: e.g. chemical medicines, lab chemicals (potassium permanganate, sulphuric acid)

Powder, liquids, pastes, and other items with danger signs on their packaging

Biochemical products and infectious materials of all kinds: e.g. bacillus anthracis, dangerous pathogens, medical wastes

Biochemical products and infectious materials of all kinds: e.g. bacillus anthracis, dangerous pathogens, medical wastes

Other restrictions will apply due to national laws and regulations of specific airlines. One example is that following the discovery of bombs on a flight due to leave the UK in 2010, the Government imposed a temporary ban on the carriage of printer cartridges from unapproved shippers.

Individuals who are sending personal effects or household items in a crate have to supply a full packing list.