Earth is an element of permanence, it stands resolute and endures what is thrown its way, or digs in and waits out the storm
we see this exemplified in
-stone skin
-burrow mechanic
-plate armor
-High DR shields
It also has a connection with permanents and things composed of more rigid and / or inanimate substance. I.e. it has a connection with permanents, and pillars and pendulums in particular
-Protect Artifact
-Earthquake (and tsunami cross element mechanic)
-Golems (hematite and cross element lava golem)
-Pulverizer
Air on the other hand prefers avoidance for survival
-Sofr
-Fog shield
-Wings
It prefers to hit swiftly and to overwhelm in a sudden strike
-Dive
-Sky blitz
-Shockwave
It also has a pension for ranged weapons / attacks. This is something that might be worth expanding (e.g. have ranged creatures which can gain some kind of benefit vs shields)
-Owl's Eye
-Bows
So the question is, how can we combine the two?
... One interesting idea is to play off of the contrast.
For instance, a creature which starts burrowed but, upon unburrowing gain flying and enhanced dive.
Effectively that quadruples (or perhaps more) its attack for 1 turn.
During its first turn out, it could also have a bonus evasion (corresponding to its unpredictable and abrupt emergence from ground to sky) or alternately, a shield bypass chance (or both).
Dust storm is another way to go.
It could be similar to thunderstorm but also cause all creatures to have an increased miss chance and / or deal less damage.