ADL says it has fine-tuned the mod package for the 737-800 to gain additional fuel burn savings after validating its technology during initial 737-700 trials.
United's added capacity will come in part from operating larger aircraft on primarily leisure routes, like using a Boeing 737-700 on flights from Key West.
SkyUp is continuing its international expansion into ACMI and charter flights after Russia's invasion of Ukraine put paid to its previous business model.
The aircraft-maker has finished its proposed redesign of older 737 nacelles, but it must analyze maintenance-related errors to help mitigate their risk.