On Thursday, May 11, 2017 at 10:16:44 AM UTC-5, Alex wrote:
Advanced is just a different map view similar to the google-maps option which also requires a login. Both options are available after logging in. There is no subscription fee.

The OLC does invite you to donate - but the only advantage is a smiley beside the claimed flights. To my knowledge the donation is purly voluntary and does not come with any special features.

I believe the "advanced" view requires not only an account login, but also a small donation to OLC. The Google view requires login only and there are a limited number of times per day you can view flights.