Refueling is the process of replenishing fuel in vehicles, aircraft, or machinery to ensure they can continue operating. This can involve adding gasoline, diesel, or other types of fuel, depending on the engine type. Refueling is essential for maintaining the performance and efficiency of transportation systems. In aviation, refueling can occur on the ground or in the air, using specialized equipment. For example, military aircraft often use aerial refueling to extend their range without landing. Proper refueling procedures are crucial for safety and to prevent accidents related to fuel spills or fires.