My unit with an attack trigger enters a battlefield and kills a unit. My opponent then uses Ride the Wind to bring a unit into the battlefield. Does my attacking unit get to use the attack trigger again?

No, your attacking unit does not get to use its attack trigger again.

According to Rule 383.4.e.2.a and the Patch Notes (2025-10-24), attack triggers only trigger once per combat, specifically the first time a unit gains the attacker designation during that combat. Even if a unit leaves and re-enters the battlefield or if the combat state changes (such as an opponent moving a new unit in via Ride the Wind), the unit cannot trigger its attack ability a second time within the same combat.

As noted in the RiftJudge FAQ (ID 4303): "Each unit can only trigger their on attack or on defense trigger once per combat... If the combat ends and a new combat starts, triggers can activate again." Since the combat is still ongoing, the trigger condition has already been satisfied for that unit for this combat.