Exhibit 99.1 Sun Country Airlines Reports Second Quarter 2025 Results Revenue of $264 million, highest second quarter on record GAAP diluted EPS of$0.12, operating income of $16 million and margin of 6.2$0.14, adj. operating income of $18 million and margin of 6.8% (1) (2) (2) (2) MINNEAPOLIS. July 31, 2025. Sun Country Airlines Holdings, Inc. ("Sun Country Airlines," "Sun Country," the "Company") (NASDAQ: SNCY) today reported financial results for its second quarter ended June 30, 20 ...