If you're worried about range I'll just tell you this. I've had a 2.6m sailplane, to where I could barely see which way it was going, and pointed the antenna straight at it, and never got any signal loss.

You're right of course about the lower frequency signals progating differently but most of us don't fly behind trees often

Proper installation is critical in any radio installation, 2.4 just requires a slightly different approach than a 3 foot antenna hanging out of the fueslage, no dobut at all about that.

I'm also not knocking 72mhz systems, I still fly one.