No, it's not illegal to ship perfume by air. Perfume is allowed on board, including limited quantities in carry on luggage and for sale in on board duty free shops.
However, when shipping perfume by air using a shipping company, the sender must declare it according to IATA's Dangerous Goods Regulations. Perfume is flammable by nature and any flammable items require special packaging, labelling and dangerous good shipping declaration. Actual requirements vary depending on the quantity being shipped (for example, in certain cases perfume samples are excepted from declaring, but still require special packaging).
Waft's global shipping partner is DHL Express and all shipments are prepared and declared strictly according to international regulations.