a routine air transport service operated in accordance with a time-table, a series of flights each possessing all the following characteristics: - it is performed by aircraft for the transport of passengers or passengers and cargo and/or mail for remuneration, in such a manner that on each flight seats are available for individual purchase by members of the public (either directly from the air carrier or from its authorized agents), - it is operated so as to serve traffic between the same two or more points, either: 1) according to a published timetable, or 2) with flights so regular or frequent that they constitute a recognizably systematic series