Telekinesis was a big pain. You got it way later when you could sneak through the Necrohol and not get beat up with two hits. By the time I got/knew about where to find it I barely had any use for it anymore. Luckily, Reddas, whom is your later guest, comes with telekinesis. Still, one character with it, much less a guest, won't do you much good.
Using most magicks on flying enemies drains your mp quickly so I never bothered doing that unless I had to. Attacking with ranged characters was fine but I only had one in my main party with a bow so that was annoying(is too lazy to change weapons for characters who use different types).
What I did for flying enemies was either ignore them or go in first with a non-ranged weapon and let them get targeted. Then, I had them use balance (I forget when it's available to you) while attacking with the ranged weapon user. When the targeted character got too hurt, I just healed them. Balance takes a lot less mp than most magicks.
I'm probably not helping much but I figured I'd share.