Do I need a license to flight test a homebuilt seaplane at very low altitude? I am asking this because me and my friends are building a homemade seaplane or boat whatever you want to call it. It's not designed for long-range or high-altitude flights. We're not going to fly at a typical altitude of normal planes/seaplanes but we're just flying it to test it. Do we require a license to fly it? 

This is in Canada and it's a manned aircraft.
14 CFR §1.1 defines an aircraft as “means a device that is used or intended to be used for flight in the air.”  Flying boats are intended for flight in the air.  Therefore.....