Travel search engines used to be big business. They still are, but they're hurting, and not a small part of it is due to Google having a onebox of flight info. I personally love that onebox - I book all my flights through it - but I'd have a hard time explaining how it's not anticompetitive. Vertical integration can have some great efficiencies, but it can also destroy once healthy markets, and I only see that getting worse with modern supply chain management and similar technologies.