CCU-DAC-CCU. My flight to Dhaka was scheduled for 1930 hrs and since I was connecting from an Indian domestic flight I had arrived at Calcutta Airport at noon time. Sitting in the lobby of the international terminal I received a phone call from Biman informing me the flight would be delayed until 2230 (although the departure information board right above me was still showing "Scheduled"). To their credit BG offered free dinner. We finally departed 2330 i.e. 4 hours late. Can't understand why an airline whose main base is only 40 minutes flying time away cannot rearrange its planes to avoid a 4-hour delay. Returning four days later flight was on time but check-in was extremely slow due to repeated incursions by uniformed staff holding bundles of tickets and passports of pax who were not in the queue. When I finally complained the staff member in question told me that he was actually checking in himself "as crew" and therefore had priority. Further questions revealed that he was not operating crew and simply felt that paying passengers come last in the scheme of things. BG have a lot of customer service training to do.