Content of Thesis : Development in technology of telecommunication and information affects the airlines to apply e-ticketing. According to the definition of e-commerce, e-ticketing can be defined as the transactions of buying and selling airline's tickets through the internet. Transportation agreement made by an airline and consumers in e-ticketing is formed as electronic ticket, not as paper ticket. Consumers are obligated to pay fully, when buying the airline's tickets through the internet. This is caused by the fact that consumers are in a weak position, wherein consumers might suffer from losses if the airlines breach the agreements. Indonesia does not have a specific law to regulate e-commerce yet. It causes uncertainty in society to transact in e-ticketing. Regarding to the nonexistence of specific laws of e-commerce, the e-ticketing and its legal aspects are based on related existing laws. Electronic ticket bases on the principle of freedom of contract valid as a law to the parties who made it as long it fulfill four requirements of a legal agreement. The four requirements consist of agreement between the parties, capability of the parlies, certainty of terms, and consideration. Then, an airline is obligated to pay compensation due to breach of the electronic tickets, which is valid as a law to the airline and consumers.