The continental United States. For purposes of the regulations in this subpart, the term “continental United States” includes only the 48 States existing on July 25, 1956 (the date of the enactment of the Act of July 25, 1956 (Pub. L. 796, 84th Cong., 70 Stat. 644)) and the District of Columbia, including inland waters (such as rivers, lakes, bays, etc.) lying wholly therein, and, where an international boundary line divides inland waters, such parts of such inland waters as lie within the boundary of the United States, and also the waters 3 nautical miles (3.45 statute miles) from low tide on the coast line. For purposes of the regulations in this subpart, the term “continental United States” does not include Alaska or Hawaii for any period either prior or subsequent to their admission into the Union as States.

The 225-mile zone. For purposes of the regulations in this subpart, the term “225-mile zone” means that portion of Canada and Mexico which is not more than 225 miles from the nearest point in the continental United States. Whether any point in Canada or Mexico is more than 225 miles from the continental United States is to be determined by measuring the distance from such point to the nearest point on the boundary of the continental United States.

Uninterrupted International air transportation. (1) For the purpose of the regulations in this subpart, the term “uninterrupted international air transportation” means transportation entirely by air which does not begin in the United States or in the 225-mile zone and end in the United States or in the 225-mile zone provided that:

Where the transportation within the United States involves one stop, the scheduled interval between the beginning or end of the United States portion of such air transportation and the end or beginning of the remainder of the air transportation, and

Where the United States portion of such transportation involves two or more stops, the scheduled interval between the beginning or end of one segment and the end or beginning of the continuing segment of such portion does not exceed six hours. The transportation is considered to be entirely by air even though the passenger may use other means of transportation between two airports provided the scheduled six-hour limitation for his continuing air transportation is complied with. Transportation which otherwise is uninterrupted international air transportation does not cease to be such because of the use of non-air transportation between ports or stations which are outside the United States, provided the non-air transportation is not part of transportation which is indirectly from one port or station in the United States to another port or station in the United States.

Where the interval between arrival and departure time at any stopover point in the United States exceeds six hours, such transportation is not uninterrupted international air transportation even though the schedules of the air lines do not make possible a scheduling within the six-hour limit. Where any interval scheduled for six hours or less is increased to exceed six hours, the transportation will continue to be uninterrupted international air transportation if the increase in time is attributable to delays in the arrival or departure of the scheduled air transportation. In such case the transportation shall continue to be uninterrupted international air transportation if the passenger continues his transportation no later than on the first available flight offered by the continuing carrier which affords the passenger substantially the same accommodations as originally purchased. However, if for any other reason such interval at any stopover is increased to more than 6 hours, the transportation will lose its classification of uninterrupted international air transportation. The tax applicable in such case shall be paid as provided in paragraph (a) (2) of § 49.4264(c)-1. The transportation from the point of orgin in the United States to a port or station outside the United States and the 225-mile zone, with a stopover in the United States, must be scheduled before the time the initial transportation commences in order for the United States portion of such transportation to qualify as uninterrupted international air transportation. For example, where transportation by air from Chicago to New York only is scheduled in Chicago and transportation by air from New York to London, England, is scheduled by the passenger after his arrival in New York, the Chicago to New York trip does not qualify as uninterrupted international air transportation even though the passenger may depart on the London flight within six hours after arrival in New York.