Both the Draenor and Broken Isles Pathfinder requirements (from the Warlords of Draenor and Legion expansions respectively) have been removed with the Shadowlands pre-patch. Once you learn Expert riding, you'll automatically be able to fly in these zones without having to earn the Pathfinder achievements first.

Will BFA Pathfinder be removed in Shadowlands?

Unlock Battle for Azeroth (BFA) Flying in Shadowlands

Unfortunately, the requirements to unlock BFA flying remained unchanged with the launch of Shadowlands. This means you will need to earn two achievements to unlock flight — Battle for Azeroth Pathfinder, Part One, and Battle for Azeroth Pathfinder, Part Two.

Will you be able to fly in Shadowlands?

As with previous WoW expansions, Shadowlands will let you fly (apart from in the introduction quest) from level 50 onwards once you've unlocked it on one character. As always, this will vastly improve, and speed up the overall leveling experience in Shadowlands.