This is a tough spot for you to be in. Sure, you think things will be ok, but some part of you probably (forgive me for saying so) is thinking "it serves you right if the plane goes down", right? I don't mean you wish her harm exactly, just that you don't really feel the need to pat her on the back and make her feel "ok" about certain aspects of this R she has with the OM.
Then you have those feelings like "am I just being an a-hole and should I just be nice?"
Here's what I do. I almost never hold back in expressing something like reassurance of my W's safety if she ASKS me to do so. I won't simply offer that to her anymore. I used to do that and I think she thought of it as condescending, as if I was reassuring her because I thought she could not do anything without my blessing that it would be ok.
It's another of those fine lines. In your case last night, I guess I would say it would have been ok to say the plane SHOULD make it to it's destination but the problem is that in order for you to do that, you would probably have felt the need to add something in about how you don't agree with the trip, etc. You chose to keep quiet, and you even told her why you were doing it.
The bottom line (and there are a TON of those, eh?) is that she WILL have emotional responses to what you do, especially if it's not in line with what she wants to see or hear. Tough noogies. Sorry charlie. You have made it clear that there are just some things you can't be there for right now, but that you WILL be there if the situation changes. You both will have to take emotional risks if this is to work. You are taking most of them now, and when she starts, this will be the first one she faces...your sincerity in terms of your changes and your intentions towards her.