Suske and Wiske
Belgian author/artist Willy Vandersteen's Suske and Wiske have been around for quite some time.
Five of the seven main characters can be seen in the illustration at the left, from #163, The Flighty Butterfly. Reading from left to right, they are: Tante Sidonia (Wiske's aunt), Wiske, Lambik (a pompous but good-hearted friend of the family), Suske (who seems to be Wiske's brother or cousin, but is actually a stray the family unofficially adopted early in the series) and Schanulleke (Wiske's doll, who doesn't usually fly). Missing here are Jerom (another friend of the family, who speaks in clipped semi-sentences but has superstrength which often saves the day) and Professor Barrabas (a brilliant scientist whose tele-timemachine sends the group into the past for many of their adventures, and whose souped-up helicopter carries them off to present-day escapades).
There are officially over 250 titles in the series, but that figure is actually misleading. The first 66 episodes were published in black-and-white; numbers 67-132 are the same books, reissued in color, and then the series continues from there. I only have about 20 of them, and some time between #177 and #226 Vandersteen must have died or retired: although his name continues to appear at the top of the front cover of subsequent books, an interior credit names Paul Geerts as both author and artist.
Six of the books were published in English (with Suske and Wiske renamed "Spike and Suzy"), but unfortunately they didn't sell well enough to justify translating further titles. There's a nice unofficial website here.