Make life easy for the person who decides if you should be interviewed. He or she is reading hundreds of these things each day. The last thing they want is another application full of platitudes and glittering generalities.
The cover letter should effectively say, "I want to work for Mesaba, meet all of the qualifications, and desire the opportunity to prove my worth in an interview.
Anyone under thirty probably hasn't done enough to warrant a resume over one page in length. Don't repeat anything that is in the cover letter or Mesaba application. Redundant information shows a lack of organizational skills. Don't pad.
Patronizing platitudes (How wonderful Mesaba is) puts a ? on your credibility. How do you know ? You don't work here.
Keep all paperwork short, to the point, and honest. Write for your audiance (HR screeners) - not the Chief Pilot. THe HR screener makes three piles - definitely yes, definitely no, and maybe. It's the last one that might get a higher level or pilot review for decision.