Philosophically I agree with JB on most things, including the idea that your word should be good once given.

The only reason I entertain these discussions about breaking contracts is because it's known that some of these employers will not uphold THEIR end of the bargain once they get a pilot on the contract hook. That, or severe personal circumstances, are the only good reasons to break a contract without paying. For the most part it's just business so if you want to break the contract and pay the note, OK fin especially at a big operator like a regional.

Bear in mind that some small operators are seriously impacted if they lose someone unexpectedly, and the note (even if paid off) might not cover their overall loss.