Do airplanes ever need extended down time?
 

If you had a plane flying between DTW and say AMS back and forth with 1-2 hour turn around times could it just continue doing this for weeks/months/years if you have the cargo/passengers? Do airplanes need "down time"? Obviously if something mechanical happens it needs to be taken care of and if a plane is sitting it is bleeding money (as opposed to making money).
Insight? Thoughts? I just watched a youtube video following a Lufthansa cargo MD11 go around the world in 66 hours and I'm assuming it just kept going round and round with 2-3 hour stops the entire way.

Lufthansa Cargo Video I mentioned
http://www.youtube.com/watch?v=sh5U-w_9NuI

There is scheduled maintenance required at various intervals (normally measured in hours, with some possibly tied to cycles). These include what are known as A, B, C, and D checks. Some of these might require weeks. Planes also occasionally get interior refurbs, which may or may not be done during the checks mentioned above.

Do airplanes ever need extended down time?
 

For LH cargo A checks are ~ every 2 weeks (A check is usually 1 day). C checks are more spread apart and D is heavy maintenance.

Most airlines would overlap refurb with a C check so that the aircraft is down for a fewer days

Love the video. ^

When a plane spends the night at a hub with maintenance facilities, the airline typically tries to use the opportunity to correct noncritical maintenance issues that have been reported, such as broken tray tables. Other than this, planes don't need rest or anything like a good night's sleep as people do.

However, maintenance schedules depend on the number of cycles (takeoffs and landings) performed as well as total flight hours rather than the absolute age of the airframe. The heavy maintenance checks are expensive. Some carriers seem to be better than others in keeping up with preventive maintenance to make mechanical delays less likely or less severe.