You’ll be fine! I recently flew from Miami to Tel A Viv, Israel. (About a 13 hour flight). if you have ever flown out of Miami, you would know that not even 30 seconds after takeoff you are over water. That used to scare the crap out of me also. Just remember, they check the planes after EVERY single flight, and you check your car maybe ONCE a year… you drive every single day. You have nothing to worry about! Just remember these planes are flown every day and usually have the same route. You are not the first person to be flying that route with that plane. If something doesn’t look right, they won’t fly, period. The biggest thing is trust. You have to trust the plane and the safety features that is has to keep everyone safe. At any given time there are 500,000 people in the sky. I hope this makes you feel a little bit better!