The enchantment Tangleroot, which reduces the melee attack of the enchanted creature, cannot be cast on a creature that has the Flying trait. It also cannot be revealed on a creature that has the Flying trait. However, the current ruling is that those are the only two times that the spell checks targeting, so if the creature gains Flying after Tangleroot has been revealed, then it will keep both. It will be a Flying creature with a reduced melee attack until Tangleroot goes away.