To further determine the role of endothelial Cpt1a in modulating neonatal hyperoxia‐induced pulmonary hypertension, we evaluated pulmonary arterial wall thickness in vessels with an outer diameter <100 μm in EC‐specific Cpt1a KO mice and their WT littermates exposed to hyperoxia as neonates. This evidence concerns the gene CPT1A and pulmonary arterial hypertension.