According to the fleet renovation and the short age of all their aircraft (6.5 years), what happens to Ryanair's aircraft after their time in the company? Are there other companies willing to accept Ryanair's aircraft configurations?
Most of Ryanair's fleets is sold upon delivery and leased back from lessors. The lessors will then lease the aircraft out to another airline for as long as its safe for the aircraft to be flying.
An example for MSN 29921 would be:
EI-CSF 24. May 2000 Ryanair C-FTCX 28. Mar 2008 CanJet OK-TSJ 05. May 2015 Travel Service C-FTCX 05. Nov 2015 CanJet C-FTCX 04. Dec 2015 Air Transat SP-ENO 30. May 2016 Enter Air