Most glues don’t work on PETG. CA and some epoxi based kind of work, but the bond is nowhere near strong enough for airplane parts. I have tried Metylacrilate (chemical welding), which does work, but the problem is it is too thin to succesfully glue the internal structure – especially wings (fuselage worked quite fine for me).
PETG has the odd ability to fuse with your buildplate. No matter what you will be printing on you will need a transition layer of glue stick or spray of some kind. It is very possible that you break chunks outof a glass type bed with PETG. I print on one of those magnetic type build surfaces and thats great with gluestick.