"I can't believe I let some Whirlybird thing beat me!"
-Percy, Races, first season
Harold is a helicopter.
- Season 1 - Races, Where's BoCo?, Bears (cameo), and James and the Ice Cream
- Season 2 - Sodor Snowstorm, Dares, Water Cannons, and Breakdown
- Season 3 - Flying Edward, Worriful Whiff (cameo), and Sea Rescue
- Season 4 - Thomas, Percy and the Hurricane
- Season 5 - Harvey and the Railway Inspectors (does not speak) and The Early Whirlybird
- Season 6 - Forest Fire,
- Season 8 - High Winds