Lipid nanoparticle (LNP)-based delivery of CFTR mRNA holds promise for treating pulmonary manifestations of cystic fibrosis (CF). LUNAR-CFTR is a novel proprietary lipid nanoparticle (LNP) encapsulating codon-optimized human CFTR mRNA for CFTR replacement therapy. In this study, we examined the potential of LUNAR-CFTR for delivering mRNA and restoring CFTR function in primary human and ferret airway epithelia and mucus-laden CF ferret airways. LUNAR effectively delivered CFTR, Cre, and tdTomato...