Archer Aviation (ACHR -4.91%) is a stock that only more aggressive investors will want to look at. That's because it is a start-up that doesn't generate any revenue or profits. And yet the opportunity ahead of this aviation business could be hugely exciting, with 2025 likely to be the year that Archer Aviation, literally, takes off.Here's what you need to know -- and why $13.30 is an important number to think about.What does Archer Aviation do?Archer Aviation has created an electric vertical takeoff and lan ...