Don't blame anyone for wanting to know the answer to that question, (lol)
The opposite side of the Earth from Norwich Airport is in the middle of the ocean, with no land for hundreds of miles around.
The nearest airport to that spot is on the Chatham Islands, several hundred miles East of New Zealand's South Island. If you'd like to browse the internet for flights, it's IATA Airport Code is CHT.
Discover more about them here