Honestly, why bother with the cover letter I think? Personally I've been told to save the cover letter for when they reply back saying their interested in your hours and experience.
Send a 1 page resume that lists your relevant jobs and experience, your hours, ratings and endorsements and your references. Having helped with the process of hiring and after going through a few dozen a week for a couple of weeks (Think I must have read about 60 different resumes after 2 weeks and there were three of us culling them!!) when you're already busy at work and trying to find time to go through them the cover letters start to blend together because they're usually all the same generic crap, so unless you've got some pretty awesome story telling/self marketing abilities I wouldn't bother wasting their time or you're going to try for the playboy route!! If fact sometimes I barely made it through the cover letter because it was just so boring or poorly typed, at least the resume itself is light on the grammar requirements and if they're interested in your hours/experience then they might not even care about the cover letter so much as the meet and greet or the subsequent telephone call.
Mind you, we've all had this discussion (Argument) before, and it all comes down to the Chief Pilot as an individual and what they like, I can only offer my own experience!!