Thanks! I also did these wooden pieces, using actual poster prints, so when it comes to decoupage, there is no paper too large to use. I like to wad the paper up into a ball to soften it and "age" it, smooth it out, then glue it on. When I'm decoupaging papers this large, I use my fingers on top of the print, swirling the glue in small circular motion, pushing out the bubbles, and causing it to look old and canvas-like. Does that make sense? Especially with this type of art. But with the suitcases, I liked the soft matte look with the crispy clean scrapbook papers, so instead of putting decoupage glue on top to seal it, I used matte spray acrylic sealer. And no way would I put it in on the conveyor belt on an airplane. Those guys really know how to tear up luggage.
Happy decoupage, everyone!