NEW YORK CITY: Mired firmly in third place during the 1996-97 televison season, ABC execs needed to do something to shake things up. Their solution? Frequent flyer miles. The Disney network announced it will give out miles on American Airlines to anyone who will watch their shows. The catch is that there's homework involved: You have to fill out questionaires to prove you watched shows like 'Ellen' and didn't just hear the highlights at the office. ABC did not say how many miles you could get through the program, or whether you would get more credit for watching an hour-long drama over a half-hour comedy. More important, there's no word on whether honchos from the network that brought us 'Family Matters' considered the apparently novel thought that maybe their ratings would improve if they put on better shows.