Please try out the new data APRS export tool. There are no links to it from the web site yet. User account and login required. Feedback welcome, as usual!
It can export to KMZ (zip'ed KML + embedded symbol graphics in the same file, for Google Earth), CSV (opens up nicely in Excel, but seems to require some tricks in OpenOffice), JSON and XML (for the programmers out there).
This feature is aimed at people who wish to download their balloon's track afterwards, or their path to Dayton and back.
It's not aimed at people who wish to download the whole aprs.fi database, so it's rate limited quite heavily. Also, it's not an API. I'll probably set the limit to 3 downloads per day per user, although for the beta test, it's currently set to 10 downloads per day per user.