Airberlin (Berlin-Tegel) has agreed with TUI Travel to cross share stock with its TUIfly (TUIfly.com) (Hanover) subsidiary. Airberlin will purchase up to 20 percent of the TUIfly stock and take over TUIfly’s European inter-city routes. TUIfly’s charter section will remain with TUIfly.  In turn, TUIfly Travel will purchase up to 20 percent of the stock of Airberlin. This agreement is subject to regulatory approvals. If approved both airlines will keep their brands.