Like the concept, but it needs significant work on the interface, which doesn't follow a number of conventions. For example, entering times - one can't enter in 24 hour time (eg 1600 for 4pm), but need to type 4, then tab to 00, then tab to the AM/PM field and then use the mouse to choose am/pm. The date fields are also problematic. You can't type in 3/27 and have it complete it as 3/27/07, you have to type in 3/27/07. It doesn't pre-populate the arrival date, either - you'd think it could figure out that a flight that leaves at 0600 and arrives 1000 was arriving on the same day, just as a flight that leaves at 2300 and arrives 0600 was arriving on the next day.
There are other more problematic issues. I entered a flight a couple of times only to find the data lost when I clicked elsewhere in the window. The interface needs to be more clear on what you need to do to save the record. Hitting 'enter' on the keyboard doesn't save the data entry as it should but instead appears to lose the entry.
Overall a nice concept, and something I'd use (I fly over 100k miles a year and would love a database for my frequent flyer miles - it would be great to have the ability to track FF miles by carrier), but it's not ready yet for prime time.