It is set to reappear along with all of Ash's Pokemon in an upcoming episode of Best Wishes Season 2.
Noctowl is the only Pokemon in Ash's team that is capable of using damaging Psychic-type attacks.
Yuji Ueda who plays Brock in the Japanese version of the anime voices Ash's Noctowl in both versions of the anime.
Heracross is one of the four Pokémon (five if Haunter is counted) that Ash owns that has a unique type combination; the others being Torterra, Scraggy, and Krookodile. Out of these, Heracross is the only Pokémon under Ash's ownership that can't evolve.
Noctowl is also the only shiny Pokémon in the anime to sparkle when it leaves its Poké Ball.
Noctowl is the only one of Ash's bird Pokémon to have been fully evolved when it was captured. As such, Noctowl is also the only Flying-type Pokémon currently owned by Ash that did not evolve under his ownership.
To date, Noctowl is also the latest Pokémon that Ash has caught it in its fully evolved state.
Noctowl is Ash's only Pokémon able to use damaging Psychic-type moves.
Noctowl is Ash's only Normal/Flying Pokémon that doesn't know Quick Attack or Wing Attack.
Despite Pokédex entries in the games stating how Noctowl can fly without making a sound, Pikachu was able to beat Noctowl by listening to the sound of its wings.