I am a romantic and love flowers but complete strangers giving them to me would freak me out.
I understand why you are doing this at an airport as it seems plane travel is very much a part of your lives.
I think if YOU met her with the bouquet of flowers and then dropped to one knee that would be a romantic proposal. Getting strangers involved in such a personal moment seems a bit icky to me.
All the very best for your future life together.