Question about FFC: I had to call United's agent in order to get our 2 business class tickets using FFC: Denver -> Lisbon outbound , return from Porto -> SFO in May. I tried to reserve on the website using our FFC but it would not go through and kept giving me an error. When I called, I told the agent I have specific flights that I would like to book (they all appeared on my result pages from the search). However the agent kept saying she could only book us on the Air Canada flights from Denver -> Toronto -> Lisbon, but not Swiss Air from Porto -> Zurich ->SFO. I explained to her that the Swiss flights kept coming up on my search so if I cannot use FFC to book, why did they keep coming up? Then her supervisor came on the phone and said "One of the flights has to be United"...but I thought FFC are usable on other Star Alliance airlines e.g. we are able to book on Air Canada. At the end she put us on Lufthansa flying Porto -> Frankfurt , then on UA Frankfurt -> SFO. We dislike the 6am flight out of Porto but it did not look like we had many other choices unless we were willing to pay a lot more $$ to cover the fare differences on other flights. So my question is why did the Swiss Air flights kept showing up on my search but it is not bookable? I started the search by using our FFC on my UA account so the system should know that I am using FFC? We would much rather be on Swiss since the flight time is better and we like this airline, although it does not look like we will be able to get on it. I am just curious how the system really works.