A couple of options. First, you could buy a fully refundable ticket; these are usually pretty extensive (think full fare coach, which are usually on par with business class prices). You may want to talk to a consolidator and determine if there are better prices for the the flight then offered via the airline, directly. The other option, if available to you, is to use frequent flier miles. Although a word of caution, each airline has certain conditions, relative to freq. flier miles and may not let you re-deposit the miles if your friend doesn't make the flight. Also, if you're using freq. flier miles, on short notice, you will probably need to 'spend' double the miles to get a seat, particularly if your friend is coming from Europe. Good luck