Donder10 is right, most of the traffic flying high over STR is probably flying to BRU and LHR/LGW/etc. and similar directions. On a sunny afternoon, you can see *many* BA 747/757/777, Airtours, Britannia, Monarch etc. and we used to see many Sabena aircraft as well.
However, I didn't have time to do "sky-spotting" today
was it sunny at all