Yup, biro or felt-tip pen somewhere around the inside door regions but I generally find crew are happy to tell you if you ask nicely. Normally always results in some merry banter too about being an anorak or such like which is fun.

Personally I keep a record of the Date:Route:Flight No:Miles:Cruise Height:Aircraft type:Reg:Captain name:SFO name:senior crew name:Takeoff runway and finally landing runway and anything further interesting, e.g on sector 20th Jan AMS-LHR BA435 operated by A320 G-EUTK as announced by the captain that this was the second commercial flight of that aircraft. silly things like that really.

FC