MANY times I have occasion to phonetically spell with Filipina call centers and they ALL use the military, Alpha, Bravo, Charlie, Delta etc.
In Boy Scouts we learned Able Baker Charlie Dog, so I imagine this changes over time.
LOL, yeah , “pass behind flight XXXX “ means let them go first ( a vague generic command), but that assumes the helicopter has a good visual on the correct target, IMO a better command would have been to “slow airspeed to XXX until flight XXX passes” ( a Blackhawk can slow down pretty fast, it had six miles to react and didn’t need to be going as fast as it was on a vector path with a landing jet