Avelo’s first revenue-generating flight was in April 2021, nearly four years ago. Since then, its fleet has grown to 20 aircraft, averaging 16.8 years, meaning they’d be less fuel-efficient and more maintenance-heavy but much cheaper to acquire. They don’t have to be used as intensively as newer alternatives. It has 12 189-seat Boeing 737-800s and eight 149-seat 737-700s.