AaronOfBarbaria
Adventurer
A very good point.With Flyby, you have the option of getting half-cover consistently (hides behind you or another party member). 3/4ths and full cover is harder, but if it's available Flyby let's you get back to it. It's definitely not foolproof, but it mitigates some risk.
There is no language in the Help action that makes it's timing for the "within 5 feet of you" any different than any other action that can be done against a target at the same distance, such as making a melee attack. Sure, the attack has a roll involved that can be used to separate things out so that you are sure you can move away after having attacked, but that doesn't mean that it is any less clear that you can move away after having helped.I am not sure help works when you fly ayway.
Also, the elements in the game that provide a benefit conditionally upon being in the appropriate place at the time of some thing happening use the word "while." As such, if the Help action required you to be within 5 feet of the intended target of the attack at the same time as the attack is made it would read "attacking a creature while it is within 5 feet of you." instead of how it does read.
Lastly, the argument of going with what "makes narrative sense" when needing something to guide how to interpret the rule: The help action lists "distract the target," as explanation of how it does what it does - is harassing the target while moving away, such as a bird "dive bombing" the target's face/head and flying away provoking a reflexive look in the direction it flew (to see if it is coming back at you, or even a "what the heck was that?" look) not a reasonable enough way to "distract the target"?