In a flight never carry any of the items mentioned below
Many flights do not allow to carry any kind of liquids or fluids including perfumes, hairspray, shampoos have been banned recently due to safety measures (please check with your air flight company)
Under no situation carry drugs, heroine, brown sugar and any other kind of narcotics.
Needless to mention although never carry any kind of compressed gas cylinders like oxygen, butane, and aqualung.
Corrosives such as acids, alkalis, mercury and wet cell alkalis or fireworks, guns and flares
Lighters, matches, magnetized materials, offensive irritating materials, medicines without prescriptions.
(there are few other items that are banned in certain countries that might even lead you to imprisonment so be extra cautious not to break any rules and never forget to ask for a travel law copy from an agent)
Inside Countries Law
If your flight is full and you want to quit it voluntarily always ask for better incentives if you feel you are not offered well.
If your luggage is expensive and you want to declare a higher value then please do it at the time of check in so...