Now now...there are a lot of FTers who travel all the time and thus compare the airport/airplane to a McDonalds, etc. But many of us don't get to fly that often, especially in J, so it's a real treat and something special.

I would inform the flight attendants at the beginning of the flight so they treat you well during the flight, enough to arouse suspicion that something might be up. Then towards the very end of the flight do the proposal with a champagne toast from the cabin distributed in advance.

Also: make sure the answer is yes