Really interesting; Bout half are hovering over mil bases, but the other half are flying generally towards military bases with a hovering partner, and those flight paths originate at civilian airports, all at about the same time. Conclusion; either they all got called home at the same time, took off and are flying at about 100mh (slow), or they all loaded up a 'package' at about the same time and are delivering it to a military base that has a blackhawk hovering in waiting, or they are practicing approach and defense maneuvers with/against a partner (standard training exercises) probably the later, but Interesting none the less