One of the coolest things I’ve seen were two Chinooks doing a simultaneous in flight refuel from one of those big tankers/jets. The Chinooks had to fly at top speed and the tanker had to fly at minimal speed, which also resulted in a gradual descent for the tanker. They started at a high altitude and the chopper pilots had to match the tanker’s decent as they refueled, then broke off when they reached the tanker’s hard stop.