Have you done anything other than send your CV? - sounds like you're really into this airline. I've done the same thing with an airline to no avail. Then I tried ringing to ask if they'd received my latest CV. Some people meet this with a little bit of shortness and others fully understand your situation. On one occasion I asked and the lady actively fished my CV out from her pile while on the phone and gave me some clues as to when they'd be hiring again and what I should do.
One other thing I started doing was addressing letters Dear Sir/Madam. WRONG!!
It shows a lack of background work on your part. Stay away from mail merge was the advice I was given. I've no doubt I'm showing you to suck eggs but if I'm not, there are some useful links on here that I've read. They talk about popping your head round doors at the airlines and networking at bars local to the airfields!