I thought you always used "an" if the next word starts with something spoken as a vocal. So, a UFO, an FAQ, an hommage to the best card.
Of course, if you say ufo and faq as if they were words instead of acronyms (we germans tend to do that with Ufo, at least), it's going to look weird to you. I can say a UFO and an FAQ both look weird to me, but they should be correct from my knowledge of your language.