In French, "pingouin" is the name for a flying bird[0] though very few people know it and most mix up pingouins (auks) with manchots (penguins, literally "armless"). Saying that penguins can fly is technically correct but people will laugh at you unless you are prepared to spend a long time explaining it.
I think it's a shame that a teacher would mislead a child the way yours did.
Having worked with penguins (the flightless ones) though, I have to say that while they are funny they didn't strike me as the most interesting or intelligent birds ever. I was quite disappointed, they regularly die by getting stuck in seaweed lying on the beach, and just keeping trying to walk straight until they get exhausted and fall. You get more meaningful interaction with a crow or even a common blackbird.