The wording of METEOR SWARM, a 9th level spell, starts with:
Blazing orbs of fire plummet to the ground at four different points you can see within range. Each creature in a 40-foot-radius sphere centered on each point you choose must make a Dexterity saving throw. The sphere spreads around corners.
When my monster cast this on the group, there was a bit of confusion due to the wording of the spell. A player pointed out that because of the phrase "plummet to the ground," the meteors must impact the ground. That being the case, any creature that is flying above 40 ft would be outside of the range of the spell. Is this the intention of the spell?
While this at first seemed plausible, I ruled that due to the phrase "sphere centered on each point you choose," I could choose to have the meteors explode at any point in the air, making flying creatures reachable targets.
Another point is that spells that explicitly limit their area effect to the ground tend to say so unambiguously. Examples include:
EVARD'S BLACK TENTACLES
Squirming, ebony tentacles fill a 20 foot square on ground that you can see within range.
The ground in a 20 ft radius centered on a point within range twists and sprouts hard spikes and thorns.
Also, the spell specifies that it is a sphere, and limiting it to the ground would necessarily limit the spell to a hemispherical range.
Lastly, it's a 9th level spell. By 17th level, most PCs can fly, and aerial battles are common. It doesn't seem likely to me that the intent of the spell was to limit it to the ground. And of course there's also this: https://en.m.wikipedia.org/wiki/Chelyabinsk_meteor