Sun Country Airlines will acquire five secondhand Boeing 737-900ERs starting in 2024. Sun Country will acquire a single 737-900 in 2024 and four 737-900s in 2025. The aircraft are currently under lease from Oman Air. Currently Sun Country operates a mixed fleet of 53 aircraft consisting of a single Boeing 737-700, Boeing 737-800s and 737-800 cargo aircraft operating on behalf of Amazon. The Boeing 737-900 will enable Sun Country to increase capacity and range when compared to the Boeing 737-800. Sun country has recently announced an expansion out of their Minneapolis Saint Paul hub (MSP) adding over 15 routes to their current route network. Sun Country has put out a press release regarding the Boeing 737-900ER acquisition. Bookings are currently available to the end of December, 2023.