Cabotage

For Example
A Canadian registered aircraft cannot legally fly into the U.S.A. to pick up passengers and fly them to another destination in the US. In order to make the flight not cabotage, the Canadian registered aircraft would have to fly the passengers they picked up back to Canada.

Cabotage is a situation where an aircraft pick up passengers or cargo in a country, not of its own registry, and discharges or ends the trip in the originating pickup country.