The only 1/100 models I'm aware of are from Decapod on Shapeways. They have a small range of WWI planes in that scale;
Hannover CL IIIa
Fokker E III
Sopwith Pup
Sopwith Triplane
Pfalz D XII
They're quite nice, with decent detail, but being prints they're a little pricy at £10-12 a piece (though that's about the same as the Wings of Glory pre-paints). Most of the planes out there seem to be in 1/144 - Wings of Glory scale - if they'll do, there are hundreds.