Dog flies a glider, it launches by sliding down hill.
Dogs can ride snow sleds and control skateboards. (see links)
They should be able to fly gliders as well. Basically a snow sled with wings.
I'm also thinking it might be possible for them to get a rolling glider up to speed on a flat surface, jump on it and shift their weight so it aims the wing equipped skateboard up long enough to do a short glide.
No ailerons, too heavy, just the twist wing control surface like the Wright Flyer used.
Now you'd probably need the pooch to launch into a good enough headwind but it would be flying dogs, which is after all, the goal here.
Credits: doctorremulac3 of HalfBakery.
Just fun to imagine.
I guess some breeds of dogs are small and fast enough to lift off all on their own, but wings would likely impede the acceleration, so, we could make wings that expand when certain windspeed is registered, and released back to normal when lifting weight becomes negative.
So, I'm imaging a dog that expands the wings automatically, when reached appropriate speed (could be done easily with air-loaded pistons, which would release the air to retract, small battery and a pump could restitute the pressure)