Just the fact that Drew asked TM to rent a storage unit in his own name and allow Drew to use it, tells us Drew had a plan in mind......one in which he would need to store a dead body and evidence for a short period of time. He wanted a storage unit that couldn't be traced back to him.
I think when TM refused to rent a storage unit for Drew, Drew found someone else to rent one........someone who owed Drew and someone he could trust not to talk. It's entirely possible too, that in lieu of a storage facility, Drew simply used someone's garage.....again, someone who could be totally trusted.
I think the trip to Cushing airport to put the FAA stickers on his ultralight was a cover for meeting someone to make arrangements for permanent disposal.