If you create a mod with the following biomes.xml file in the Config folder, it will "fix" the sky in the wasteland. (Basically, it swaps out the wasteland sky for the pine forest sky. But be aware it does this regardless of if you are flying... and it doesn't really feel right.)
<config>
<setattribute xpath="/worldgeneration/biomes/biome[@name='wasteland']/spectrum" name="name">pine_forest</setattribute>
</config>