Not big, but very efficient.

When picking up the car, they gave us a Mazda 5 in great condition, only driven for 6000 km. It was filled up with gas, and we just needed to return it with a full tank. Returning the car at the airport was convenient; we just handed back the keys and didn't need to go through an inspection. Of course, we were careful throughout the trip and didn't encounter any issues. We'll continue to choose car rentals for self-driving trips in the future!

I mentioned to Ayana Mahamed (who was working the counter at National at the Calgary Airport) that my wife and I took this trip to celebrate our 25th anniversary, and he VERY graciously upgraded us from a tiny economy car to a small luxury SUV. He was awesome. National is awesome. We are SO grateful :)

Like: We were offered an upgrade to a 2018 Volstwagon Passat which had more leg room and trunk space than the booked car. We were very happy with the fuel efficiency, how the car drove and quality of the vehicle.
Dislike: We were under the assumption that Hertz would fill the tank for us at their discounted rate, however didn't know that they would charge us for a full tank regardless of how much fuel was in there.

Like: The car was new, in great condition and everything was working perfectly. Drop off was extremely quick and efficient and I really appreciated that. I would gladly rent again!
Dislike: The location was a little hard to find and when I tried to phone to receive directions, nobody answered. However, I ended up asking airport staff how to get in and they told me.