From the article you linked to:
"ADS has estimated that it would take 10 years and cost up to £40m annually to create a UK safety authority with all the expertise of EASA, against a current contribution to the European agency of £1m to £4m a year."
This is not the only certifying or regulatory authority that UK is losing access to and of which they have to create their own instead of chipping in together with 27 other countries. Will create some UK jobs and a huge UK cost..
Continues:
"It claimed a new regulatory regime could put jobs in the sector at risk."We have been clear that continued participation in EASA is the best option to maintain the competitiveness of our £36bn aerospace industry and our access to global export markets," the trade body said.
It added that the UK's influence within EASA "contributes to raising standards in global aviation" and helped make the industry "attractive to the investment it needs".
British Airways owner IAG said it was "disappointed" with the decision and said the Civil Aviation Authority "does not have the expertise required to operate as a world class safety and technical regulator".
IAG said: "The CAA will require fundamental restructuring from top to bottom which will take time. There is no way that it can be done by 31 December."