Yes. Depending on the mission, military aircraft use either their standard Squadron / Wing callsigns with tail#, or a randomly assigned callsign from an ATO (Air Tasking Order) if conducting combat coded missions. Most callsigns are 4-6 characters in length, and designed to be easily understood. Also, the ATO is designed such that no two callsigns would sound similar with each other so they won't be misconstrued in a reduced comm / jamming situation.