Empty leg ferry flights?

 An empty leg is where an aircraft is required to position to a particular airport for a one-way charter or returns to its base empty.

Ferry flights, colloquially known as ‘empty leg flights’, are trips a private jet charter makes without a designated set of passengers to board the plane. Ferry flights are a broad concept that is known by different names all around the world, such as empty leg flights, empty leg of a private charter, and e-positioning flights. Ferry flights is an aviation term for this type of mode of flying, the others are better known among the flying personnel.