In 2026, global aviation security remains extremely strict regarding what is prohibited in checked luggage to prevent fires and structural damage. You are strictly forbidden from packing flammable liquids (like lighter fluid, gasoline, or spray paint), explosives (including fireworks, flares, and even realistic toy replicas), and compressed gases (like camping propane or diving tanks). A critical and often misunderstood rule involves lithium batteries: while they are allowed inside devices (if powered off), "loose" or "spare" lithium-ion batteries and power banks are completely banned from checked suitcases and must be carried in your cabin bag where they can be monitored. Additionally, items like bleach, acid, and mercury are prohibited due to their corrosive nature. For international travel, many countries also ban the transport of fresh meat, fruit, and soil in suitcases to prevent the spread of agricultural diseases. Always double-check with your specific airline, as some also prohibit high-value items like cash and jewelry in checked bags due to the risk of theft.