I got it off. The glue was pretty hard. A plastic razor blade had no impact. I surrounded the glue with masking tape and went after it with a steel razor blade. It final popped off! No chemicals needed.
Its always best to wax the airplanes 1st, so glue doesn't stick. I seem to get glue somewhere unwanted everytime, its my trademark. The older I get, the less I care. There will always be another airplane.