Air Jet operates flights between Delhi and Darjeeling, a tourist destination, which takes approximately 2 hours. Pilots

Question:

Air Jet operates flights between Delhi and Darjeeling, a tourist destination, which takes approximately 2 hours. Pilots report to duty based on where they were hired. For example, if a pilot, David, was hired by the Delhi branch of the airline, then he should report to duty at the Delhi airport every day. David starts his piloting or idle run from Delhi and reaches Darjeeling and returns to Delhi on the same day. Based on the optimum schedule, the airline fixes the reporting airport for every pilots on its pay roll. It is also possible for a flight to fly one additional pilot to a city to fly a return flight if there are not enough pilots in that city. Between flights, pilots should have at least one-hour rest time called ground time. The airline wants to determine the optimal schedule of pilots to minimize the ground time.