Originally Posted by
s25843
The grammar rules I was taught many moons ago, was to use AN when the first letter of the next word is a vowel.... An apple, An Idiot, An Airplane...
It's a grey area when it comes to the written word. If I'd written the sentence, I would have said "a FF," since "FF" is an abbreviation of "frequent flyer," and you wouldn't say "an frequent flyer."