It sounds like she doesn't want to feel obligated to you. Perhaps she doesn't want to owe you one. A lot of human interactions are transactional, maybe she is of impression that she will still have to pay you back "somehow". And that "somehow" can be a scary thought.
Though, why would you want to pay for her ticket anyway? Personally, I don't think I would accept someone else buying me a plane ticket, even if it was the most beautiful woman in the world. I wouldn't want to feel like I'm in someone's pocket.
Not a plane ticket.... a show ticket.. It's like 42 dollars... Thanks
Well Bro .. I Guess, She Is Thinking As In Positive Way And She Is Worried If You Will Take Her Wrong, Let Her Pay For Her Ticket And Joke Around With Her, Bring A Flower, But Not A Read One And She'll Be Happy