The research firm based its analysis on proprietary data collected from airlineticket vendors and by surveying ticket prices on the Internet, among other techniques.
Otherwise, it might end up buying an airlineticket when what the end-user really wanted was a book.
否则，虽然最终用户真正希望是一本书，但最后买到的却是一张飞机票。
3
Adding to rail's competitive advantage, European environmental policies are likely to force an increase in airlineticket prices over the next few years.