JJflyer, the airline I work for (single type airline) crew about 6 to an aircraft, and we fly an average of about 75 a month. Some of the low cost airlines crew as little as 4-5 crew per aircraft and as we know they are guaranteed to fly 900 hours a year. SAS on the other hand crew more like 7.5 to an aircraft. The main reason for this is that SAS flies long haul which has completely different crewing requirements than smaller regional/european carriers. Also the fact that Finnair and SAS have mixed fleets add to the number of crews required as they are not as flexible to roster as a single type operator would be.