We flew JetBlue down for the wedding.
What I did was purchase an extra seat on the way down for my dress.
When I called Customer Service, we had a good laugh when I said what I wanted to do - but then she told me to just book the seat as "Extra Seat Monahan."
The seat was only like $70 - and it also entitled us to the extra baggage allowance - which we used to check boxes of welcome bag items that would not need to come back to NY. Cheaper than shipping the items UPS.
Then when we checked in, the allowed us priority boarding.
The one thing the flight attendant insisted on was that I buckle the dress in - we got a good laugh about that!
We only paid for the ticket one way - since Carolyn Allen's was picking up my dress for cleaning after the wedding.
I know it sounds silly but it really gave me peace of mind - and the dress never left my sight once.