I think proposing on an A380 is perfect for an avgeek - but is your partner an avgeek? If not, I would suggest it would not be her "fairytale".
Personally, I would go for somewhere that will have a sentimental value for both of you (or maybe more-so for her!).
Personally, I would go for somewhere that will have a sentimental value for both of you (or maybe more-so for her!).