Something I learned a few weeks ago: Put 1/3 cup kernels in a large brown paper lunch bag and fold the top down several times. Microwave as normal, bag standing up, listening for pops to slow down. Air pops in the bag with no issues. Salt (and ghee) after you dump it in the bowl. I have stopped using my whirlypopper.
You can even staple the bag closed. But now I'm a whirlypop convert. Coconut oil and flavacol popcorn salt. Yum.
I used to work at a movie theater, this is the way.