A.
First of all, DGR 2.3.5.6 stipulates that “One small packet of safety matches or a cigarette lighter that does not contain unabsorbed liquid fuel, other than liquefied gas, intended for use by an individual” may be carried “on the person”. “Matches and lighters are not permitted in checked or carry on baggage.”

Zippo type lighters do not have a sealed fuel tank but the liquid fuel is normally absorbed in the cotton swab that is filled in the fuel tank. Some airlines reject Zippo type lighters with reason that the fuel tank does not have a lid and is not sealed.

Other airlines permit Zippo type lighters as the fuel tank slides tight into the casing and demonstrates an almost sealed condition. You will need to check with the particular airline.