As it seems to be a hot topic at the moment I thought a I'd do a quick blog post about flying stands. I'm of the opinion that it always part of the design to make certain models unreachable within the Age of Sigmar rules set, remembering that bases aren't part of the the model unless house ruled.
Essentially any model on a flying stand can potentially be protected by the fact that a model cannot come within 1/2" to complete a charge. Or if it does end up in combat it is out of weapon range.
The reasoning behind this is directly from the main rules (bases and charging) and also confirmed by the Terradon Rider's swooping dive rule, which otherwise is useless.
When bases are house ruled in, this doesn't work and actually changes how effective a unit may be and whether it's worth using for its points as it may have been pointed with the fact that it's not chargeable in mind(although I doubt this would make much difference in reality).
So considering this I have come up with a few areas where these units can be effective:
• They can be used to attack large monsters without being bothered by smaller units within the same combat. For example, your Terradon Riders attacking a Gargant but immune to the attacks of nearby Grots.
• They can be used to block movement of units without being able to be charged. You can place your flying unit in a way so units have to move around you as they could not come within 3" during movement unless they charged, which isn't possible.
• Hold objectives without being charged. Fairly self explanatory, although worth double checking the wording of the scenario to make sure.
• They can attack units on higher terrain pieces that may have no more room for troops. If for example a unit is fully occupying all levels of a Dreadstone Blight there's only a small gap for foot troops to attack, however your flying units can attack those models on the higher levels without entering the scenery itself.
I hope this post has opened your eyes to how to use your units on flying stands more effectively in casual games. Just remember that they're still susceptible to to ranged attacks and magic so they're not invulnerable!