A good example is an arrangement that Miami Air, a US charter carrier, and Excel have entered into. Miami Air and Excel share a 737-800... Summers in England, and Winters in the US. A select few Miami Air Pilots come to England and obtain a validation. They fly the Excel aircraft when in the US during the winter months, and England during the summer months. A select few from Excel get a US ATP so they can act a crewmembers on the US registered aircraft.