Flight Sofia - Louisville, KY prices from £379.77

Aegean Airlines is the largest airline in Greece, operating both domestic and international flights to over 150 destinations. Founded in 1987, the airline has grown to become a major player in the European aviation market, with a fleet of over 60 aircraft and a reputation for high-quality service. Aegean Airlines is a member of the Star Alliance, a global airline network that includes some of the world's largest carriers. The airline has won numerous awards for its customer service, including the Skytrax award for Best Regional Airline in Europe for nine consecutive years.

Air Canada is the largest airline in Canada, providing scheduled and charter air transportation for passengers and cargo to over 200 destinations worldwide. The airline operates a fleet of over 400 aircraft, including narrow-body and wide-body jets, and serves both domestic and international routes. Air Canada is a member of the Star Alliance, a global airline network that provides passengers with access to over 1,000 destinations in 190 countries. The airline offers a range of services, including in-flight entertainment, Wi-Fi, and a loyalty program called Aeroplan. Air Canada is headquartered in Montreal, Quebec, and has hubs in Toronto, Vancouver, and Calgary.

Air France is the flag carrier airline of France, headquartered in Tremblay-en-France. It is a subsidiary of the Air France-KLM Group and a founding member of the SkyTeam global airline alliance. The airline operates a fleet of over 200 aircraft, serving more than 200 destinations worldwide. Air France offers a range of travel classes, including Economy, Premium Economy, Business, and La Première (First Class). The airline is known for its high-quality service, comfortable seating, and in-flight entertainment options. Air France is committed to sustainability and has implemented various initiatives to reduce its environmental impact, such as investing in more fuel-efficient aircraft and reducing single-use plastics.

Alaska Airlines is a major American airline headquartered in Seattle, Washington. It was founded in 1932 and operates a fleet of over 300 aircraft, serving more than 115 destinations across the United States, Canada, Mexico, and Costa Rica. Alaska Airlines is known for its commitment to customer service, on-time performance, and sustainability initiatives. It is a member of the Oneworld airline alliance and has codeshare agreements with several other airlines. Alaska Airlines offers a variety of travel classes, including First Class, Premium Class, and Main Cabin, as well as a loyalty program called Mileage Plan.

Allegiant Air is an American low-cost airline that operates scheduled and charter flights. It was founded in 1997 and is headquartered in Las Vegas, Nevada. The airline operates flights to over 120 destinations across the United States, including popular vacation destinations such as Las Vegas, Orlando, and Myrtle Beach. Allegiant Air operates a fleet of Airbus A319, A320, and A321 aircraft, and offers a range of services including seat selection, priority boarding, and in-flight entertainment. The airline has been recognized for its low fares and customer service, and has won several awards for its performance and reliability.

Bulgaria Air is the national flag carrier airline of Bulgaria, headquartered in Sofia. It operates scheduled flights to over 20 destinations in Europe, the Middle East, and Africa. The airline was founded in 2002 and has a fleet of 10 aircraft, including Airbus A319s and Embraer E190s. Bulgaria Air offers both economy and business class seating, as well as a frequent flyer program called Fly More. The airline has codeshare agreements with several other airlines, including Air France, KLM, and Alitalia. Bulgaria Air is a member of the International Air Transport Association (IATA) and the Association of European Airlines (AEA).

Lufthansa is a German airline and one of the largest airlines in Europe. It was founded in 1953 and operates flights to over 200 destinations worldwide. Lufthansa is a member of the Star Alliance, which is the world's largest airline alliance. The airline has a fleet of over 300 aircraft, including Airbus and Boeing planes. Lufthansa offers a range of services to its passengers, including in-flight entertainment, Wi-Fi, and a frequent flyer program called Miles & More. The airline is known for its high-quality service and has won numerous awards for its customer satisfaction and safety standards.

Qatar Airways is the national airline of Qatar, based in Doha. It was founded in 1993 and has since grown to become one of the world's leading airlines, with a fleet of over 200 aircraft flying to more than 160 destinations worldwide. Qatar Airways is known for its luxurious and award-winning service, offering passengers a range of amenities such as lie-flat seats, gourmet cuisine, and in-flight entertainment. The airline is a member of the oneworld alliance and has partnerships with several other airlines, allowing passengers to easily connect to destinations around the world. Qatar Airways has won numerous awards for its service, including being named the world's best airline by Skytrax in 2019.

Spirit Airlines is an American ultra-low-cost carrier that operates flights throughout the United States, the Caribbean, Mexico, and Central and South America. The airline was founded in 1983 and is headquartered in Miramar, Florida. Spirit Airlines is known for its low fares and no-frills approach to air travel, with passengers paying extra for amenities such as checked baggage, seat selection, and in-flight refreshments. The airline operates a fleet of Airbus aircraft and has a frequent flyer program called Free Spirit. Despite its low-cost model, Spirit Airlines has faced criticism for its customer service and fees.

Turkish Airlines is the national flag carrier airline of Turkey, headquartered in Istanbul. It operates scheduled flights to over 300 destinations in Europe, Asia, Africa, and the Americas, making it one of the largest airlines in the world by number of destinations served. Turkish Airlines has won numerous awards for its service, including "Best Airline in Europe" six years in a row from 2011 to 2016. The airline operates a modern fleet of over 350 aircraft, including Airbus A320s, A330s, A340s, A350s, and Boeing 737s, 777s, and 787s. Turkish Airlines is a member of the Star Alliance, the world's largest airline alliance.

United Airlines is a major American airline headquartered in Chicago, Illinois. It is one of the world's largest airlines, operating a comprehensive domestic and international network of flights. United Airlines operates a fleet of over 800 aircraft, serving more than 350 destinations in over 50 countries. The airline is a founding member of the Star Alliance, which is the world's largest airline alliance. United Airlines offers a range of services to its passengers, including in-flight entertainment, Wi-Fi, and a loyalty program called MileagePlus. The airline has a strong commitment to sustainability and has implemented various initiatives to reduce its environmental impact.