Because you don&#x27;t have the money on hand to return it to flight (ie a part needs replacement).  Or it is being held by some creditor and its storage should be called a seizure.<p>There are lots of very expensive parked planes.  Ever watch the mythbusters?  All the stunts they do with jet engines are with a group of parked 747s.  The engines have to be runup every so often to maintain flight readiness.