How often are aircraft maintained? The answer is complicated and depends on a variety of factors. Aircraft are finely tuned machines designed to fly safely over long distances without a hiccup. They are designed with backup systems and sometimes backups to those backups. Aircraft are exceedingly complicated machines – after all the Airbus A380 has over a million parts. Airliners need a large workforce of engineers to maintain their aircraft (e.g., Qantas states that Qantas Engineering has over 3300 people to maintain its fleet). Scheduled aircraft maintenance provides the obvious benefits of preventative maintenance, allowing airlines to fix their aircraft before they break down – leading to downtime or worse.