Air traffic control stations often have insufficient numbers of air traffic controllers, sometimes just one person on duty. In a recent study, a lone air traffic controller is managing an airstrip in which the expected time between arrivals of airplanes is 15 minutes. Assume that the times between consecutive arrivals are independent Exponential random variables. If he falls asleep for a period of 5 minutes, what is the probability that one or more airplanes arrive during this period (but cannot land because the air traffic controller is not awake to guide them)?