Decreased respiratory function is a common side effect experienced by non-small cell lung cancer (NSCLC) patients who receive radiation therapy. In current clinical practice when treating cancerous lesions in the lung, it is not standard to explicitly try and avoid excessive radiation dose and therefore radiation injury to smaller airways. However, because of this patients may obtain damage to an airway segment can cause downstream regions in the lung to lose their "supply line" and, therefore, cause patients to lose the ability to exchange oxygen with the blood. The purpose of this clinical trial is to systematically compare post-treatment lung function of those who receive regular clinical radiation therapy (standard of care \[SoC\]) versus those who receive the airway-sparing radiation therapy regimen. The investigators hope to show that, by preserving airways and connected lung regions, participants will be able to retain a larger amount of their lung function, which will have a direct, positive impact on their post-treatment quality of life.