Anxiety over flying pregnant

So far so good right now with everything. My biggest worry is my upcoming honeymoon. We will be flying to Mexico & plan on doing some snorkeling & adventuring. I'm the most worried about the flight & the possibility of going into labor or something while there!!! My doctor is giving me permission to go & writing a letter for the airline. I asked her about the possibility of having the baby there & her only response was "I guess he'll have dual citizenship then". I guess we'll see. The honeymoon was paid for over a year ago & given to us as a wedding gift...we've already changed it once & my honey-pie really needs a vacation. I'm just scared to go & scared I'll be no fun at all while there. I'm crossing my fingers that it all goes smoothly!