The world naturally evolves to prevent accidents, but it also must maintain a balance. Therefore, although the Beastmen had an air force, they wouldn't use it recklessly, and it wouldn't be too powerful.
But Du You knew how things worked, the people of this world didn't.
"These Hawkmen are too dangerous, we cannot let them be. We don't have enough soldiers to control two cities, if the Beastmen attack, we'll hardly hold up. If they have an air force, it will be even more dangerous."
"You don't intend to attack those Hawkmen, do you? No, that's the air force. If you provoke the Beastmen, they will surely launch an attack." Some in their stronghold immediately objected.
Du You waved his hand: "We must take precautions. The Beastmen are our enemies. If they know our current situation, they will surely fight. Don't think they know nothing about us, don't forget that they've colluded with the people of Wood Shield City."