Repairing certain parts of a MacBook Air (or Pro) over 5 years old could be difficult. For older Macs, many find themselves on eBay; salvaging faulty parts since Apple doesn't have them available for repair anymore. This means it may be up to you to salvage the broken part on your own and try to get an Apple service provider to assist you in replacing it. This is costly. Sometimes AppleCare won't be able to help as vintage parts aren't always available/covered.