From Bulbapedia, the community-driven Pokémon encyclopedia.
Miles (Japanese: マイル Mile) is a recurring character of the Pokémon anime and the former Gym Leader of the Mistralton Gym.
In the anime
Miles first appeared in Cilan Takes Flight! after Ash and his friends had just met Skyla. He had retired from being the Gym Leader of Mistralton City in order to fulfill his dream of owning his own cargo business. His granddaughter took over for him after his retirement. Like Ash and Cilan, he did not agree with Skyla's concept of using "Air Battles" to run the Gym. He then explained that she used to battle challengers the traditional way and was also very good but battling them left her no time to fly her plane, thus she came up with the concept so she wouldn't waste her time. Although he disagreed with Skyla, he thought she might still have a point and thus gave up trying to convince her otherwise, only doing so again once Ash challenges Skyla to a proper battle himself.
Miles now serves as the Gym assistant for his granddaughter and refereed both Cilan and Ash's match. Before Skyla had battled Ash, she watched old videos of Miles battling challengers while he was Gym Leader so she could pick up tips.
He appeared once again in Climbing the Tower of Success! where he hosted the Wishing Bell Festival. There it was revealed that he is very knowledgeable of important female figures in Unova, mostly because he finds them attractive. Elesa happens to be his favorite and even disqualified Cilan in the contest because his impression of her was not up to his standards.
In the games
It is mentioned that Skyla has a grandfather in the games as well but he was left nameless. It was said that he was once a great pilot.