Main transit hubs in Europe usually are the ones which have the cheapest fares. From my own own working experience, I’ve observed that London, Amsterdam, Frankfurt and Milan are usually cheaper to fly into than other smaller sized towns. Look on flight search engines like yahoo like Kayak®⁵ or Skyscanner®⁶ https://sound-social.com/story9750107/facts-about-how-to-find-cheap-flights-to-europe-from-the-us-revealed