In a three-airline town, the company with the heart logo is striving to show Denver who loves it the most. And it plans to demonstrate its affection by pumping $100 million into a new maintenance hangar at Denver International Airport. Southwest Airlines CEO Gary Kelly opened his company’s annual shareholders meeting in Denver on Wednesday morning by describing the city as “without a doubt the fastest-growing city in the history” of the low-cost carrier. Based in Dallas, Southwest first came to DIA in 2006, getting a modest start with only 13 daily departures and three nonstop destinations.