How Elon Musk Runs His Famously Efficient Meetings
Don't be in a meeting unless there's a purpose for it.
In a nutshell, only hold a meeting when necessary.
When I was there in 2015, SpaceX meetings were rare, but I would say they were most common in my group. I worked in Dragon Development, which is primarily project/systems engineering for the variety of Dragon products. We needed to coordinate many different groups to synchronize the assembly and hit deadlines. So getting the team leads together made sense.
One of my close friends started there a couple of years before me. He worked (and still does) in an analysis group, so meetings made less sense when you could just walk over and ask someone a question. He told me a story one time (this is paraphrased):
Elon to a meeting member: "You haven't said anything. Why are you in here?"
That may be borderline rude, but it makes sense. Don't be in a meeting unless there's a purpose for it; either to make a decision or get people up to speed. In most cases, an email will suffice.
Meetings are expensive. Assuming the fully-encumbered cost of an engineer can be between $80 to $100 per hour. Having a 10 person meeting can cost a company around $1,000 an hour!
For $1,000 per hour, that meeting should damn well be worth it.