Permission has been granted for an aviation firm to carry out limited aircraft engine testing on the ground at Norwich Airport.
KLM UK Engineering has been testing at an unauthorised site for five years.
City councillors agreed KLM and the airport could move the site and continue testing but only at 78 decibels or below.
People living nearby claim the tests are too noisy but KLM argues 400 jobs depend on them.
Although the airport welcomed the decision it said it had "grave concerns" about the impact of the restrictions, which they may appeal against.
The tests have also been limited to be carried out on weekdays between 0800 and 2000 BSTand between 1000 and 1600 BST at weekends.
Resident Valerie McNally, who lives at Horsham St Faith, said she was disappointed at the proposals.
Mrs McNally claimed she could could hear the tests over and above her television and that her windows vibrated.
"KLM and the airport haven't sufficiently thought about the lives of the people in the area," she said.
"I'm disappointed they have not made better noise mitigation systems."
Andrew Bell, chief executive of Norwich Airport, said: "We have worked hard to deliver the best solution to ensure KLM UK Engineering can continue their business whilst providing screening and noise reduction.
"However the permission as currently approved does not provide sufficient assurance that this is the case.
"We are now planning to provide more evidence to support our assertion that KLM UK Engineering's business may be hindered by the current upper noise limit and the further restriction of testing times at weekends. "
KLM UK Engineering argued the future of its business and 400 people it employs rested on approval of its new engine testing site.