Buses - S1.E7

Auntie Mabel is in a hurry to return some books to the library before it shuts. She and Pippin get into their spotted aeroplane to fly there but the plane won't start so they have to take the bus. But in her hurry, Auntie Mabel leaves Pippin on the bus. Pippin ends up at the bus depot where she helps the driver look for lost property and sees a bus being washed and filled with fuel.