Which jurisdiction applies in a vessel?
<p>Consider an aircraft registered in country A. On a flight operated by an airliner based in country B, it carries passengers on a flight from country X to country Y. The flight path overflies airspace of country C and international airspace.</p>

<p>Assume that countries A, B, C, X and Y all have different legal drinking ages. </p>

<p>What is the legal drinking age on this flight? Does the same apply on ships?</p>

<p>The short answer is, in absence of a treaty or convention governing travel, then the law of the country over which the plane is located governs for the time the plane is in overflight. Laws of a jurisdiction (a country, or a state) are generally taken to extend upward from their boundaries (and downward for the control of mineral rights, etc.). </p>

<p>There are a number of jurisdictional cases where service of process (presenting a defendant with a copy of citation starting a civil suit) or an arrest has taken place on-board aircraft where the action had to take place over a given country or state to invoke jurisdiction.</p>

<p>As mentioned in the first sentence, there is nothing to prevent countries for entering into a Treaty or agreement that would alter the basic scheme, but absent a treaty or convention, the basic scheme of boundary extension would apply.</p>

jurisdiction international