When planning a trip to Denver, one of the first and most important decisions you’ll make is choosing which airline to fly with. Airfare often sets the tone for the rest of your journey—determining not only how much you spend, but also how comfortable, convenient, and enjoyable your travel experience will be. Denver International Airport (DEN) ranks among the busiest airports in the United States, welcoming millions of passengers each year. Thanks to its size and strategic location, it has become a critical hub for both domestic and international travel.

Because Denver sits in the heart of the country, the airport is a natural connecting point for coast-to-coast flights and a convenient gateway to the Rocky Mountains, drawing leisure travelers in search of outdoor adventure as well as business travelers heading to meetings in the city’s growing corporate sector. With a sprawling network of airlines competing for passengers, travelers benefit from abundant choices—ranging from ultra-low-cost carriers offering budget-friendly fares to full-service airlines delivering premium cabins, loyalty perks, and extensive international routes.

The challenge isn’t whether you’ll find a flight to Denver, but which airline best matches your needs. This guide explores the top options and highlights what sets each one apart.

Why Denver International Airport Is a Key Hub

Before diving into the airline breakdown, it’s worth highlighting why Denver International Airport is such a unique and strategic travel hub:

• Central location: Positioned nearly in the middle of the country, Denver is an ideal connecting point for flights heading east or west.
• Massive size: The airport covers over 30,000 acres, making it the largest in the U.S. by land area. Its expansive facilities allow for a wide variety of domestic and international airlines.
• Growing demand: Tourism, outdoor recreation, and a booming business environment mean more airlines continue to expand service here.
• Convenience for travelers: Direct flights are available to more than 200 destinations, both within the United States and internationally.

This accessibility means that when you’re booking a flight to Denver, you’ll likely have multiple options across different airlines, giving you flexibility in terms of schedule, service, and price.

Major Domestic Airlines Flying to Denver

1. United Airlines

United Airlines is the largest carrier at Denver International Airport and has made it one of its main hubs. This means frequent flights, more route options, and competitive scheduling.

Why choose United?

• Extensive domestic network with direct flights from nearly every major U.S. city.
• International connections are plentiful, especially for Europe and Asia.
• United MileagePlus loyalty program offers strong value for frequent flyers.
• Business-class cabins on longer domestic routes often come with lie-flat seating.

Best for: Business travelers, frequent flyers with loyalty to Star Alliance, and passengers seeking premium international connections.

2. Southwest Airlines

Southwest is another dominant player at DEN. Known for its affordable fares, customer-friendly policies, and free checked bags, it’s a favorite for budget-conscious travelers.

Why choose Southwest?

• Two free checked bags included, saving significant costs for families or longer trips.
• Open seating policy gives flexibility when boarding.
• No change fees, which is useful for travelers with uncertain schedules.
• Strong domestic coverage, including nonstop flights to many secondary cities.

Best for: Families, leisure travelers, and anyone prioritizing affordable, flexible travel.

3. Frontier Airlines

Denver is Frontier Airlines’ home base. As an ultra-low-cost carrier, it offers some of the cheapest fares into the city, though with additional fees for extras like carry-on bags and seat assignments.

Why choose Frontier?

• Ultra-low base fares are perfect for budget travelers who pack light.
• Frequent promotions and discounts, especially for Denver routes.
• Discount Den membership can reduce overall costs for frequent fliers.

Best for: Solo travelers on short trips, minimal packers, and budget-conscious passengers who don’t mind sacrificing some comforts.

4. Delta Air Lines

While not based in Denver, Delta has a significant presence. With strong service through its hubs in Atlanta, Minneapolis, and Salt Lake City, it’s an excellent choice for connections and premium service.

Why choose Delta?

• Consistently ranked high for customer service.
• Strong in-flight entertainment and reliable Wi-Fi.
• Delta SkyMiles loyalty program and SkyTeam partnerships provide global reach.
• High-quality premium cabins, even on shorter domestic routes.

Best for: Travelers who value comfort and consistency, as well as loyalty program members with SkyTeam partners.

5. American Airlines

American Airlines connects Denver to many of its major hubs, including Dallas/Fort Worth, Chicago, and Miami. It’s a solid option for travelers heading to the East Coast, Latin America, or connecting internationally.

Why choose American?

• Extensive international reach through oneworld alliance partners.
• Admirals Club lounges available at key hubs.
• Variety of cabin options, from Main Cabin Extra to Flagship Business.
• Consistent service for both leisure and business travelers.

Best for: Passengers connecting internationally, loyalty members of oneworld, and those who often fly through Dallas or Chicago.

6. Alaska Airlines

Although smaller in scale at Denver compared to other carriers, Alaska Airlines is known for exceptional service and strong West Coast routes.

Why choose Alaska?

• Excellent reputation for customer service.
• Strong loyalty program (Mileage Plan), considered one of the most rewarding in the U.S.
• Great option for travelers heading to Seattle, Portland, or California.
• Partnership with oneworld expands international options.

Best for: West Coast travelers, loyalty program enthusiasts, and passengers seeking a balance of affordability and comfort.

International Airlines Serving Denver

While domestic airlines dominate, several international carriers also fly into DEN, making it easier than ever to reach Denver directly from abroad.

1. Lufthansa

• Direct flights to Frankfurt connect Denver with Europe and beyond.
• Excellent service in both economy and premium cabins.
• Strong loyalty benefits for Miles & More members.

2. British Airways

• Direct service to London Heathrow.
• Great option for European travelers or those connecting to other oneworld partners.
• Offers a premium experience in Club World business class.

3. Air Canada

• Direct connections to Canadian cities like Toronto, Vancouver, and Montreal.
• Convenient for Canadian travelers heading to Denver for business or skiing holidays.

4. Icelandair

• Seasonal flights to Reykjavik provide unique one-stop access to Europe.
• Great for combining trips to Iceland and the U.S. in one journey.

Choosing the Right Airline for Your Travel Needs

Every traveler has different priorities, so here’s a quick guide to matching airlines with your specific travel style:

• Budget-conscious travelers: Frontier Airlines, Southwest Airlines
• Frequent flyers & business travelers: United Airlines, Delta Air Lines, American Airlines
• Families: Southwest Airlines (for free bags), United Airlines (for broad route options)
• Luxury travelers: United Polaris, Delta One, British Airways Club World, Lufthansa Business Class
• International visitors: Lufthansa, British Airways, Air Canada, Icelandair
• West Coast travelers: Alaska Airlines, Southwest Airlines

Tips for Booking Flights to Denver

1. Book early for peak travel periods: Demand around holidays and ski season drives prices up quickly.
2. Compare baggage policies: A cheap ticket may not be a bargain once fees are added.
3. Use loyalty programs wisely: Choose airlines aligned with your frequent flyer status.
4. Consider timing and delays: Afternoon thunderstorms in Denver can cause delays, so morning flights are often more reliable.
5. Check nearby airports: If you’re flexible, sometimes flying into nearby cities like Colorado Springs can offer savings.

The Future of Air Travel in Denver

As Denver continues to grow in popularity as both a business hub and a leisure destination, airlines are responding by adding more routes, increasing flight frequency, and investing in better services for passengers. Frontier Airlines is rapidly expanding its network of ultra-low-cost options, making it easier than ever for budget-conscious travelers to reach the Mile High City. United Airlines is doubling down on its role as Denver’s largest hub carrier, strengthening connections not only within the United States but also to major international destinations. At the same time, global airlines such as Lufthansa, British Airways, and Icelandair are recognizing Denver’s strategic importance as a gateway to the western United States, creating more direct links between Colorado and the rest of the world.

For travelers, this growing competition between carriers translates into tangible benefits. Increased capacity often means lower fares, while the diversity of airlines ensures that every type of passenger can find a flight that matches their preferences. Whether you value flexible baggage policies, superior in-flight entertainment, generous loyalty rewards, or nonstop international connections, there is likely an airline flying to Denver that delivers exactly what you’re looking for.

Flying to Denver has never been easier or more versatile. Solo travelers searching for the cheapest deal can take advantage of Frontier’s ultra-low fares or Southwest’s frequent promotions. Business professionals who prioritize comfort and efficiency may prefer United’s hub advantages, Delta’s reliable service, or American’s international partnerships. Families, meanwhile, will appreciate Southwest’s family-friendly policies, such as two free checked bags, or the wide network of United flights that make it easy to coordinate schedules. Luxury seekers have plenty of options as well, with premium cabins on Lufthansa, British Airways, or United Polaris offering a more refined experience.

The key to a smooth journey is understanding your own travel priorities—whether cost, comfort, loyalty benefits, or convenience matters most—and aligning them with the strengths of each airline. With careful planning and the right choice, your trip to Denver will begin on the right note, ensuring that the journey itself is just as memorable as your time spent in this vibrant, mountain-framed city.