Just figured I'd mention that Air Berlin is celebrating an "Air Berlin Day" in Moenchengladbach next week (27.04), and as part of that they are offering half hour long sightseeing flights around a few cities in the area with their Bae146 for 29 Euros, throughout the day. You can book the flights online (www.airberlin.com) and on the phone, as well as on the day at the counter.
I got that from the www.airevents.de forums.
Photo © Andreas Zube
Photo © Gerardo Dominguez
Anyway, perhaps someone is interested...