What does Airbus means by long product cycles? I was reading this article. The article was about issues that Airbus may face if the UK does a 'Hard Brexit'.  At the very end of the Article though, Airbus says 


  Airbus makes wings for all its jetliners in the UK. The France-based
  company campaigned against Britain leaving the EU ahead of the UK
  vote, but has said it would not make abrupt changes to its operations
  there due to long product cycles. - foxbusiness.com 


Can anybody elaborate what the company means by long product cycles?
A long product cycle means that the lifecycle of a product spans a long time. Aircraft models are often produced for more than 30 years (the 737 and 747 are now approximately 50 years in production). 

At the same time, the capital expenses to build a production line are enormous. And in starting up a production line there are always teething troubles which take time and money to iron out. Therefore it would be a waste of capital to move a production line from the UK to mainland EU. 

That only is viable when a new aircraft model is introduced and an old model is phased out. New models don't appear every year and it seems that most of the current models are still selling well so unless there will be a huge cost associated with keeping the production line in the UK (e.g. taxes, increasing labour cost, unfavourable exchange rate) no changes are to be expected soon.