The website Airhelp.com has a pretty lofty promise on their front page.
"Claim compensation for your flight delay or cancellation
Flight delays happen, but that doesn’t mean you have to accept them. You may be entitled to as much as $700 in compensation if your flight was delayed, canceled or overbooked within the last 5 years."
Now one would think that an unpaid bill of $700 wouldn't go unnoticed by most people. However, those who have scheduled a flight that was later bumped or delayed may be entitled to compensation and not even know it!
All you have to do to find out if you have money waiting on you is enter your name and flight information. Couldn't hurt to check, right?