Aileen's craft cement ("Tacky Glue" - a vinyl glue like R/C-56) works well. Available at craft and fabric stores. Remove the covering under the areas the canopy edge contacts the fuselage. Not much sticke to covering, and if it does you might still end up with the canopy glued to the covering . . . and a bare spot where the covering tore off the fuselage (ask me how I know that). Screws are still the best if looks allow.

And a couple small holes in the cockpit into the main body help prevent the condensation and heat deformation in sealed cockpits.