No slots for SXF, it is a new base in TXL. No UK License needed, german licenses are fine, ICAO level 4 is sufficient. As far as i know the retention pay of up to 40.000€ and loyalty pay based on pay grade (not seniority) with airberlin is meant as an incentive scheme to make sure enough airberlin pilots, especially those in the higher pay grades, apply. It is a CLA signed with the local union (verdi).