Until recently, age 65 was accepted as the natural age limit. Currently, the Mayo Clinic website includes a statement that says for anyone above the age of 65, each case will be considered individually. This gives hope to older people.
A recent National Institutes of Health article via NCBI sites a recent study that followed eligible recipients below age 65, and above age 65. Generally, those recipients ages 75 to 79 showed that lowest success and survival rates (Annals of Thoracic Surgery. 2015 Aug;100(2):443-51).
One should ask their doctor about eligibility and survival chances to be certain, but older eligible people may have better chances in the future as medicine advances. My hope is that we can learn to clean and restore lung health in the future without transplantation.