I think if I were in your situation I would do a draft about what it is exactly that she does that bothers you and why (give emotional reasons, like "I feel disrespected when you check my facebook every day because I interpret that to mean that I am unable handle myself and my life, but I can't learn to handle myself if you are checking up on me so often. That makes me feel hopeless."). People can't always relate to your beliefs and ideas, but they can relate pretty well to the emotions behind them.
Then ask her if she would be willing to cut back on the outside manifestations of her worry (like checking your flight patterns), for your sake. Tell her that you understand that she's concerned about her child because she loves you, and that you appreciate that (assuming you do understand and appreciate, no fibs
), but that this is really eating you up inside.
There are empathy exercises that both of you can do. I'm sure there are some online. This will help both of you to see each others perspectives. Not saying that you have to change her mind about her, but it's helpful to know where she's coming from in order to figure out how to resolve the problem so that everyone is happy.
My mom has always been a worrier. It's just her nature. It doesn't really affect me directly much because I live 3 states away, but I've learned to accept that part of her. To me, her worry can get unhealthy, but I just let her know that I appreciate that she's concerned for me and reassure her that I'll make it through whatever difficulties I'm currently having.