In the We Bare Bears episode " Baby Bears on a Plane " (S2E15), the baby brothers sneak onto a plane, hoping for a life filled with pancakes in Sweden. The brothers are separated, leading to subplots where they face challenges before reuniting to save the day through teamwork.

[Episode starts with a plane taking off. A man is loading luggage into a plane. Grizzly, Panda, and Ice Bear are inside of a box.] We Bare Bears Wiki

You can find more details, including a summary and links to watch, on the We Bare Bears Wiki . Baby Bears on a Plane/Transcript - We Bare Bears Wiki

[Episode starts with a plane taking off. A man is loading luggage into a plane. Grizzly, Panda, and Ice Bear are inside of a box.] We Bare Bears Wiki Baby Bears on a Plane/Transcript - We Bare Bears Wiki